Initialization
This commit is contained in:
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98369fd5cf
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# Instructions
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Implement basic list operations.
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In functional languages list operations like `length`, `map`, and `reduce` are very common.
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Implement a series of basic list operations, without using existing functions.
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The precise number and names of the operations to be implemented will be track dependent to avoid conflicts with existing names, but the general operations you will implement include:
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- `append` (*given two lists, add all items in the second list to the end of the first list*);
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- `concatenate` (*given a series of lists, combine all items in all lists into one flattened list*);
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- `filter` (*given a predicate and a list, return the list of all items for which `predicate(item)` is True*);
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- `length` (*given a list, return the total number of items within it*);
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- `map` (*given a function and a list, return the list of the results of applying `function(item)` on all items*);
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- `foldl` (*given a function, a list, and initial accumulator, fold (reduce) each item into the accumulator from the left*);
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- `foldr` (*given a function, a list, and an initial accumulator, fold (reduce) each item into the accumulator from the right*);
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- `reverse` (*given a list, return a list with all the original items, but in reversed order*).
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Note, the ordering in which arguments are passed to the fold functions (`foldl`, `foldr`) is significant.
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@ -1,25 +0,0 @@
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{
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"authors": [
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"wolf99"
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],
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"contributors": [
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"patricksjackson",
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"rootbeersoup",
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"ryanplusplus",
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"xihh87"
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],
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"files": {
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"solution": [
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"list_ops.c",
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"list_ops.h"
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],
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"test": [
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"test_list_ops.c"
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],
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"example": [
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".meta/example.c",
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".meta/example.h"
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]
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},
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"blurb": "Implement basic list operations."
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}
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#include "list_ops.h"
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#include <string.h>
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list_t *new_list(size_t length, list_element_t elements[])
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{
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list_t *list = malloc(sizeof(*list) + sizeof(list_element_t) * length);
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if (!list)
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return NULL;
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list->length = length;
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memcpy(list->elements, elements, sizeof(list_element_t) * length);
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return list;
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}
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list_t *append_list(list_t *list1, list_t *list2)
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{
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if (!list1 || !list2)
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return NULL;
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size_t length = list1->length + list2->length;
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list_t *list = malloc(sizeof(*list) + sizeof(list_element_t) * (length));
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if (!list)
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return NULL;
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list->length = length;
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if (length) {
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memcpy(list->elements, list1->elements,
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sizeof(list_element_t) * list1->length);
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memcpy(&(list->elements[list1->length]), list2->elements,
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sizeof(list_element_t) * list2->length);
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}
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return list;
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}
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list_t *filter_list(list_t *list, bool (*filter)(list_element_t))
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{
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if (!list || !filter)
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return NULL;
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list_t *filtered =
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malloc(sizeof(*list) + sizeof(list_element_t) * list->length);
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if (!filtered)
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return NULL;
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size_t j = 0;
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for (size_t i = 0; i < list->length && j < list->length; ++i) {
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if (filter(list->elements[i]))
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filtered->elements[j++] = list->elements[i];
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}
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filtered->length = j;
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return filtered;
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}
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size_t length_list(list_t *list)
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{
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if (!list)
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return 0;
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return list->length;
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}
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list_t *map_list(list_t *list, list_element_t (*map)(list_element_t))
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{
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if (!list || !map)
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return NULL;
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list_t *mapped =
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malloc(sizeof(*list) + sizeof(list_element_t) * list->length);
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if (!mapped)
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return NULL;
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mapped->length = list->length;
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for (size_t i = 0; i < mapped->length; ++i)
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mapped->elements[i] = map(list->elements[i]);
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return mapped;
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}
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list_element_t foldl_list(list_t *list, list_element_t initial,
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list_element_t (*foldl)(list_element_t,
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list_element_t))
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{
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if (!list || !foldl)
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return 0;
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for (size_t i = 0; i < list->length; ++i)
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initial = foldl(list->elements[i], initial);
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return initial;
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}
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list_element_t foldr_list(list_t *list, list_element_t initial,
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list_element_t (*foldr)(list_element_t,
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list_element_t))
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{
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if (!list || !foldr)
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return 0;
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for (size_t i = list->length; i > 0; --i)
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initial = foldr(list->elements[i - 1], initial);
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return initial;
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}
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list_t *reverse_list(list_t *list)
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{
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if (!list)
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return NULL;
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list_t *reversed =
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malloc(sizeof(*list) + sizeof(list_element_t) * list->length);
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if (!reversed)
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return NULL;
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reversed->length = list->length;
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for (size_t i = 0, j = reversed->length - 1; i < reversed->length;
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i++, j--) {
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reversed->elements[i] = list->elements[j];
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}
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return reversed;
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}
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void delete_list(list_t *list)
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{
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free(list);
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}
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#ifndef LIST_OPS_H
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#define LIST_OPS_H
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#include <stdlib.h>
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#include <stdbool.h>
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typedef int list_element_t;
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typedef struct {
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size_t length;
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list_element_t elements[];
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} list_t;
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// constructs a new list
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list_t *new_list(size_t length, list_element_t elements[]);
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// append entries to a list and return the new list
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list_t *append_list(list_t *list1, list_t *list2);
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// filter list returning only values that satisfy the filter function
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list_t *filter_list(list_t *list, bool (*filter)(list_element_t));
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// returns the length of the list
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size_t length_list(list_t *list);
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// return a list of elements whose values equal the list value transformed by
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// the mapping function
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list_t *map_list(list_t *list, list_element_t (*map)(list_element_t));
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// folds (reduces) the given list from the left with a function
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list_element_t foldl_list(list_t *list, list_element_t initial,
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list_element_t (*foldl)(list_element_t,
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list_element_t));
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// folds (reduces) the given list from the right with a function
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list_element_t foldr_list(list_t *list, list_element_t initial,
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list_element_t (*foldr)(list_element_t,
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list_element_t));
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// reverse the elements of the list
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list_t *reverse_list(list_t *list);
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// destroy the entire list
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// list will be a dangling pointer after calling this method on it
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void delete_list(list_t *list);
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#endif
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# This is an auto-generated file. Regular comments will be removed when this
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# file is regenerated. Regenerating will not touch any manually added keys,
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# so comments can be added in a "comment" key.
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[485b9452-bf94-40f7-a3db-c3cf4850066a]
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description = "empty lists"
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[2c894696-b609-4569-b149-8672134d340a]
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description = "list to empty list"
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[e842efed-3bf6-4295-b371-4d67a4fdf19c]
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description = "empty list to list"
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[71dcf5eb-73ae-4a0e-b744-a52ee387922f]
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description = "non-empty lists"
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[28444355-201b-4af2-a2f6-5550227bde21]
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description = "empty list"
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include = false
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[331451c1-9573-42a1-9869-2d06e3b389a9]
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description = "list of lists"
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include = false
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comment = "C does not easily allow a single implementation for multiple types (Liskov substitution)"
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[d6ecd72c-197f-40c3-89a4-aa1f45827e09]
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description = "list of nested lists"
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include = false
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comment = "C does not easily allow a single implementation for multiple types (Liskov substitution)"
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[0524fba8-3e0f-4531-ad2b-f7a43da86a16]
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description = "empty list"
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[88494bd5-f520-4edb-8631-88e415b62d24]
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description = "non-empty list"
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[1cf0b92d-8d96-41d5-9c21-7b3c37cb6aad]
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description = "empty list"
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[d7b8d2d9-2d16-44c4-9a19-6e5f237cb71e]
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description = "non-empty list"
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[c0bc8962-30e2-4bec-9ae4-668b8ecd75aa]
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description = "empty list"
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[11e71a95-e78b-4909-b8e4-60cdcaec0e91]
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description = "non-empty list"
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[613b20b7-1873-4070-a3a6-70ae5f50d7cc]
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description = "empty list"
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include = false
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[e56df3eb-9405-416a-b13a-aabb4c3b5194]
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description = "direction independent function applied to non-empty list"
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include = false
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coment = "reimplemented"
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[d2cf5644-aee1-4dfc-9b88-06896676fe27]
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description = "direction dependent function applied to non-empty list"
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[36549237-f765-4a4c-bfd9-5d3a8f7b07d2]
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description = "empty list"
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[7a626a3c-03ec-42bc-9840-53f280e13067]
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description = "direction independent function applied to non-empty list"
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[d7fcad99-e88e-40e1-a539-4c519681f390]
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description = "direction dependent function applied to non-empty list"
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include = false
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comment = "Prefer integer division test case (d2cf5644-aee1-4dfc-9b88-06896676fe27)"
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[aeb576b9-118e-4a57-a451-db49fac20fdc]
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description = "empty list"
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include = false
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coment = "reimplemented"
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[c4b64e58-313e-4c47-9c68-7764964efb8e]
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description = "direction independent function applied to non-empty list"
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include = false
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coment = "reimplemented"
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[be396a53-c074-4db3-8dd6-f7ed003cce7c]
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description = "direction dependent function applied to non-empty list"
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[17214edb-20ba-42fc-bda8-000a5ab525b0]
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description = "empty list"
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[e1c64db7-9253-4a3d-a7c4-5273b9e2a1bd]
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description = "direction independent function applied to non-empty list"
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[8066003b-f2ff-437e-9103-66e6df474844]
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description = "direction dependent function applied to non-empty list"
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include = false
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comment = "Prefer integer division test case (be396a53-c074-4db3-8dd6-f7ed003cce7c)"
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[94231515-050e-4841-943d-d4488ab4ee30]
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description = "empty list"
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[fcc03d1e-42e0-4712-b689-d54ad761f360]
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description = "non-empty list"
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[40872990-b5b8-4cb8-9085-d91fc0d05d26]
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description = "list of lists is not flattened"
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include = false
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comment = "C does not easily allow a single implementation for multiple types (Liskov substitution)"
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Binary file not shown.
@ -39,11 +39,30 @@ list_t *append_list(list_t *list1, list_t *list2) {
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}
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// filter list returning only values that satisfy the filter function
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list_t *filter_list(list_t *list, bool (*filter)(list_element_t)){
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return NULL;
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list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
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if (list == NULL) return NULL;
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size_t filteredLength = 0;
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for (size_t i = 0; i < list->length; ++i) {
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if (filter(list->elements[i])) {
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++filteredLength;
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}
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}
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list_t *filtered = malloc(sizeof(list_t) + filteredLength * sizeof(list_element_t));
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if (filtered != NULL) {
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filtered->length = filteredLength;
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size_t j = 0;
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for (size_t i = 0; i < list->length; ++i) {
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if (filter(list->elements[i])) {
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filtered->elements[j++] = list->elements[i];
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}
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}
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}
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return filtered;
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}
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// returns the length of the list
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size_t length_list(list_t *list) {
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return (list != NULL) ? list->length : 0;
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@ -64,28 +83,47 @@ list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)) {
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}
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// folds (reduces) the given list from the left with a function
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list_element_t foldl_list(list_t *list, list_element_t initial, list_element_t (*foldl)(list_element_t, list_element_t)){
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list_element_t accumulator = initial;
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return res;
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list_element_t foldl_list(list_t *list, list_element_t initial,
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list_element_t (*foldl)(list_element_t, list_element_t)) {
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list_element_t accumulator = initial;
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if (list != NULL) {
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for (size_t i = 0; i < list->length; ++i) {
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accumulator = foldl(list->elements[i], accumulator);
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}
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}
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return accumulator;
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}
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// folds (reduces) the given list from the right with a function
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list_element_t foldr_list(list_t *list, list_element_t initial,list_element_t (*foldr)(list_element_t, list_element_t)){
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list_element_t res=0;
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return res;
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list_element_t foldr_list(list_t *list, list_element_t initial,
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list_element_t (*foldr)(list_element_t, list_element_t)) {
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list_element_t accumulator = initial;
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if (list != NULL) {
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for (size_t i = list->length; i > 0; --i) {
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accumulator = foldr(list->elements[i - 1], accumulator);
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}
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}
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return accumulator;
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}
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// reverse the elements of the list
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list_t *reverse_list(list_t *list){
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return NULL;
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list_t *reverse_list(list_t *list) {
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if (list == NULL) return NULL;
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list_t *reversedList = new_list(list->length, list->elements);
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if (reversedList != NULL) {
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for (size_t i = 0; i < list->length / 2; ++i) {
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list_element_t temp = reversedList->elements[i];
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reversedList->elements[i] = reversedList->elements[list->length - i - 1];
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reversedList->elements[list->length - i - 1] = temp;
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}
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}
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return reversedList;
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}
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// destroy the entire list
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// list will be a dangling pointer after calling this method on it
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void delete_list(list_t *list){
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}
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void delete_list(list_t *list) {
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free(list);
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}
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