115 lines
3.2 KiB
C
115 lines
3.2 KiB
C
#include "a_station.h"
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#include <stdlib.h>
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#include <string.h>
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#include <stddef.h>
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struct station* create_station() {
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struct station* s = calloc(1, sizeof(struct station));
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s->tracks = calloc(STATION_SIZE, sizeof(struct car*));
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s->track_count = STATION_SIZE;
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return s;
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}
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int select_track(struct station* s, const char* target) {
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unsigned long hash = 5381; //5381 это алгоритм DJB2
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int c;
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while ((c = *target++)) { // не забываем ++ чтобы идти по строке
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hash = ((hash << 5) + hash) + c; //hash << 5 сдвигает все биты числа hash на 5 позиций влево. Это тоже самое, что умножить на 2 в пятой степени
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}
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return (int)(hash % s->track_count);
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}
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void add_target_capacity(struct station* s, const char* target, int capacity) {
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if (!s || !target) return;
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int index = select_track(s, target);
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struct car* current = s->tracks[index];
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if (current == NULL) { //Этот кусок кода создаёт “поезд” на пустой колее.
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struct car* new_car = calloc(1, sizeof(struct car));
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strcpy(new_car->value, target);
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new_car->capacity = capacity;
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new_car->next = NULL;
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s->tracks[index] = new_car;
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return;
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}
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struct car* prev = NULL; //создаём указатель prev, который будет хранить предыдущий элемент списка
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while (current != NULL) {
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if (strcmp(current->value, target) == 0) {
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current->capacity += capacity;
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return;
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}
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prev = current;
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current = current->next;
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}
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struct car* new_car = calloc(1, sizeof(struct car));
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strcpy(new_car->value, target);
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new_car->capacity = capacity;
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new_car->next = NULL;
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prev->next = new_car;
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}
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int get_target_capacity(struct station* s, const char* target) {
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if (!s || !target) return 0;
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int index = select_track(s, target);
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struct car* current = s->tracks[index];
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while (current != NULL) {
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if (strcmp(current->value, target) == 0) {
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return current->capacity;
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}
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current = current->next;
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}
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return 0;
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}
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int count_targets(struct station* s) {
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if (!s) return 0;
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int count = 0;
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for (int i = 0; i < s->track_count; i++) {
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struct car* current = s->tracks[i];
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while (current != NULL) {
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count++;
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current = current->next;
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}
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}
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return count;
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}
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int count_capacity(struct station* s) {
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if (!s) return 0;
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int total = 0;
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for (int i = 0; i < s->track_count; i++) {
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struct car* current = s->tracks[i];
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while (current != NULL) {
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total += current->capacity;
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current = current->next;
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}
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}
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return total;
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}
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void destroy_station(struct station* s) {
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if (!s) return;
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for (int i = 0; i < s->track_count; i++) {
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struct car* current = s->tracks[i];
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while (current != NULL) {
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struct car* to_delete = current;
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current = current->next;
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free(to_delete);
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}
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}
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free(s->tracks);
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free(s);
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}
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