prvy

sk1a/main.c

@@ -10,13 +10,12 @@ void print_solution(char* matrix,int sz){
             printf("\n");
         }
     }
-
 }
 
 int main(){
     char tmaze[SZ+1][SZ+1]={
         "*x   ",
-            " xx  ",
+        "  x  ",
         "   x ",
         "  x  ",
         "     ",

sk1a/maze.c

@@ -3,86 +3,75 @@
 #include "maze.h"
 #include <assert.h>
 
-int solve_maze(char* maze,int size) {
+int issafe(char* maze, int x, int y, int size) {
-    int i = 0;
+    if ((x >= 0 && x < size) && (y >= 0 && y < size) && maze[x * size + y] == ' '){
-    int p, l, h, d = 0;
+        return 1;
-    while(i != size*size-1){
+    }
-        //if (i % size - 1 != 0){l = 1;}
+    return 0;
-        //else if (i < size*size - size){h = 1;}
+}
-        //else if (i % size){p = 1;}
+
-        //else if (i >= size){d =1;}
+int backtracking(char* maze, int x, int y, int size){
-        if (maze[i + 1] == ' ' /*&& i % size - 1 != 0 */&& l != 1) {
+    if(x == size - 1 && y == size - 1 && maze[x * size + y] == ' '){
-            maze[i + 1] = '*';
+        maze[x * size + y] = '*';
-            i++;
+        return 1;
-            p = 0;
+    }
-            l = 0;
+
-            h = 0;
+    if(issafe(maze, x, y, size) == 1) {
-            d = 0;
+        maze[x * size + y] = '*';
-        } else if (maze[i + size] == ' ' /*&& i < (size*size - size) != 0 */&& h != 1) {
+
-            maze[i + size] = '*';
+        if (backtracking(maze, x, y + 1, size) == 1) {
-            i = i + size;
+            return 1;
-            p = 0;
+        }
-            l = 0;
+        if (backtracking(maze, x + 1, y, size) == 1) {
-            h = 0;
+            return 1;
-            d = 0;
+        }
-        } else if (maze[i - 1] == ' ' /*&& i % size != 0 */&& p != 1) {
+        if (backtracking(maze, x - 1, y, size) == 1) {
-            maze[i - 1] = '*';
+            return 1;
-            i--;
+        }
-            p = 0;
+        if (backtracking(maze, x, y - 1, size) == 1) {
-            l = 0;
+            return 1;
-            h = 0;
+        }
-            d = 0;
+        maze[x * size + y] = ' ';
-        } else if (maze[i - size] == ' ' /*&& i >= size */&& d != 1) {
+    }
-            maze[i - size] = '*';
+    return 0;
-            i = i - size;
+}
-            p = 0;
+
-            l = 0;
+int solve_maze(char* maze, int size) {
-            h = 0;
+    if (maze[0] == '*'){
-            d = 0;
+        assert(maze[0] == '*');
-        }
+        maze[0] = ' ';
-        else{
+    }
-            while(1){
+    int x,y = 0;
-
+    while(x * size + y <= size*size - 1 ){
-                if (maze[i + 1] == ' ' && i != size - 1 && l != 1) {
+        printf("%d\n%d", x * size + y, y);
-                    //i++;
+        //issafe(maze, x, y, size);
-                    break;
+        if (maze[x * size + y + 1] == ' ' /*&& y != 5*/){
-                }
+            assert(maze[x * size + y + 1] == ' ');
-                if (maze[i + size] == ' ' && i != size - 1 && h != 1) {
+            maze[x * size + y + 1] = '*';
-                    //i = i + size;
+            y++;
-                    break;
+
-                }
+        }
-                if (maze[i - 1] == ' ' && i != 0 && p != 1) {
+        if (maze[(x + 1) * size + y] == ' ' /*&& x != 5*/){
-                    //i--;
+            assert(maze[(x + 1) * size + y] == ' ');
-                    break;
+            maze[(x + 1) * size + y] = '*';
-                }
+            x++;
-                if (maze[i - size] == ' ' && i > size && d != 1) {
+
-                    //i = i - size;
+        }
-                    break;
+        if (maze[x * size + y - 1] == ' ' && y != 0){
-                }
+            assert(maze[x * size + y - 1] == ' ');
-                p = 0;
+            maze[x * size + y - 1] = '*';
-                l = 0;
+            y--;
-                h = 0;
+
-                d = 0;
+        }
-                if (maze[i + 1] == '*' && i != size - 1) {
+        if (maze[(x - 1) * size + y] == ' ' /*&& x != 0*/){
-                    maze[i] = ' ';
+            assert(maze[(x - 1) * size + y] == ' ');
-                    i++;
+            maze[(x - 1) * size + y] = '*';
-                    p = 1;
+            x--;
-                } else if (maze[i + size] == '*' && i != size - 1) {
+
-                    maze[i] = ' ';
+        }
-                    i = i + size;
+        else{
-                    d = 1;
+            backtracking(maze,x , y, size);
-                } else if (maze[i - 1] == '*' && i != 0) {
+        }
-                    maze[i] = ' ';
+    }
-                    i--;
-                    l = 1;
-                } else if (maze[i - size] == '*' && i > size) {
-                    maze[i] = ' ';
-                    i = i - size;
-                    h = 1;
-                }
-            }
-        }
-    }
-    maze[0] = '*';
 return 1;
 }

sk2a/readme.md

@@ -0,0 +1,284 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "compressor.h"
+#define BUFSIZE 1024
+#define SIZE 256
+#define MAX_WORDS 100000
+
+// One codeword is previous index - new index -character
+
+// Trie (a.k.a prefix tree)
+struct dict {
+int index;
+// Character is encoded as non zero value in characters
+struct dict* characters[SIZE];
+};
+
+// Free trie
+void delete(struct dict* tree){              //skopirovane z lz78, vymaze strukturu co sa pouziva v lz78
+if (tree == NULL){                           //maze to pamat stromu
+return;
+}
+for (int i = 0 ;i < SIZE; i++){
+delete(tree-> characters[i]);
+}
+free(tree);
+}
+
+void get_words (struct dict* tree,char* words[]){					//posielam cely strom a smernik na dvojrozmerne pole
+if (tree == NULL){													
+return;
+}
+for (int i = 0 ;i < SIZE; i++){										//prejdeme vsetkych potomkov
+if (tree-> characters[i] > 0){										//zistime ci tam je nieco naalokovane
+int need_size = snprintf(NULL,0,"-%d-%c\n",tree->index,i);			//kolko pamate
+words[tree->characters[i]->index] = calloc(need_size + 1,sizeof(char));			//naalokujeme pamat
+memset(words[tree->characters[i]->index],0,need_size + 1);
+sprintf(words[tree->characters[i]->index],"-%d-%c\n",tree->index,i);			//napise sa vo formate -index predosleho notu - aktualny znak 
+
+            get_words(tree-> characters[i],words);								//zavolam na kazdeho potomka a potom na dalsich potomkov alebo syna
+        }
+    }
+}
+
+int mylz78compress(char* buff,int size,char** outbuf){
+// https://medium.com/@dbudhrani/how-data-compression-works-exploring-lz78-e97e539138
+// The trie represents the current phrase
+// The first node represents the empty string with index 0
+struct dict* root = calloc(1,sizeof(struct dict));
+struct dict* current = root;
+int index = 1;
+int c = 0;
+char *last = NULL;
+for(int i = 0; i < size; i++){
+c = buff[i];
+// Current character is in dictionary, continue searching
+if (current->characters[c] > 0){    
+// ak este nieco ostalo a toto je koniec
+if (i == size - 1){   // pridem na koniec suboru a musim si to zapamatat, inac to stratim
+int sz_needed = snprintf(NULL,0,"-%d-%c\n",current->index,c);  //kolko bajtov to bude zaberat
+last = calloc(sz_needed + 1,sizeof(char));						//alokuje do do last
+sprintf(last,"-%d-%c\n",current->index,c);						//
+}
+
+            current = current->characters[c];
+        }
+        else {
+            current->characters[c] = calloc(1,sizeof(struct dict));
+            current->characters[c]->index = index;
+            index += 1;
+            current = root;
+        }
+    }
+
+    char **words = calloc(index,sizeof(char*));					// z stromu vytvori format
+    get_words(root,words);
+
+    int size_needed = 0;		
+    for(int i=1; i < index; i++){									//nastavime velkost aku bude mat vystupny buffer
+        if(words[i] != NULL){
+            size_needed += strlen(words[i]);						//poscitavame velkosti vsetkych stringov
+        }
+    }
+
+    if (last != NULL){												//mame string last?
+        size_needed += strlen(last);								//priratam
+    }
+
+    char *temp = calloc(size_needed + 10,sizeof(char));				//alokujem velkost, padalo mi to ked som mal mensie cislo ako 10
+    int pos = 0;													//pamatam kde som to uz vypisal
+    for(int i=0; i < index; i++){
+        if (words[i] != NULL){
+            strcpy(temp + pos,words[i]);							//nebude sa to pisat na zaciatok ale az za tym
+            pos += strlen(words[i]);
+        }
+    }
+
+    if (last != NULL){											// zapisem aj last
+        strcpy(temp + pos,last);
+        pos += strlen(last);
+    }
+
+    delete(root);													//nepotrebujeme strom, uvolnime pamat
+    free(words);
+
+    *outbuf = temp;										//adresa sa zapise do outbuffer
+    return strlen(temp);
+}
+
+
+int myrlcompress(char* buff,int size,char** outbuf){
+// 2 * size je urcite dost, kedze v najhorsom pripade bude kazdy znak osamote
+*outbuf = calloc(2 * size + 1,sizeof(char));								//smernik na smernik, napisem adresu novej pamate
+memset(*outbuf,0,size + 1);													//vymaze
+
+    int head = -1;
+    int length = 0;
+    int pos = 0;
+    for(int i = 0; i < size; i++){
+        int c = buff[i];
+
+        if (c == head){
+            length += 1;
+            if (i == size - 1){				//posledne pismenko
+                (*outbuf)[pos] = head;
+                (*outbuf)[pos + 1] = length;
+                pos += 2;                                      //aby som vedel kde to zapisovat
+                break;
+            }
+        }
+        else {
+            if (head != -1){
+                (*outbuf)[pos] = head;
+                (*outbuf)[pos + 1] = length;
+                pos += 2;
+            }
+            if (i == size - 1){						  //posledne pismenko
+                (*outbuf)[pos] = c;
+                (*outbuf)[pos + 1] = 1;
+                pos += 2;
+                break;
+            }
+
+            head = c;
+            length = 1;
+        }
+
+        // ak sme blizko preteceniu, vypiseme aktualny znak
+        if (length == 255){								//nemozme ist viac, vynulujem a idem od nuly
+            (*outbuf)[pos] = head;
+            (*outbuf)[pos + 1] = length;
+            pos += 2;
+            head = -1;
+            length = 0;
+        }
+    }
+
+    return pos;    //velkost vystupneho buffera
+}
+
+
+void compress(FILE* infile,FILE* outfile){
+fseek(infile, 0, SEEK_END);                        //vstupny subor, a chceme presunut kurzor na konci suboru
+int insize = ftell(infile) + 1;						// na akej pozicii je kurzor, zistime velkost suboru
+rewind(infile);                                     //vrati kurzor na zaciatok
+char *buffer = calloc(insize,sizeof(char));          //alokuje pamat
+
+    memset(buffer,0,insize);
+    insize = fread(buffer,sizeof(char),insize - 1,infile);     //nacita obsah do bufferu
+    
+    if (insize == 0){
+        assert(!ferror(infile)); 
+    }
+    
+    char *tempbuf = NULL;											// az vo funkcii to alokujem
+    int tempsize = myrlcompress(buffer,insize,&tempbuf);			//vstupny buffer, velkost a adresu bufferu
+    
+    char *outbuf = NULL;
+    int outsize = mylz78compress(tempbuf,tempsize,&outbuf);
+    
+    if (outsize   > 0){
+        fwrite(outbuf,sizeof(char),outsize,outfile);				//napise sa do suboru, z akeho buffera do akeho suboru
+    }
+
+    free(buffer);
+    free(tempbuf);
+    free(outbuf);
+}
+
+
+int myrldecompress(char* buff,int size,char** outbuf){
+*outbuf = calloc(size + 1,sizeof(char));
+memset(*outbuf,0,size + 1);
+
+    int pos = 0;
+    for(int i = 0; i < size; i+=2){
+        char c = buff[i];
+        char length = buff[i + 1];
+
+        // ak nam nebude stacit miesto v *outbuf, treba allocovat viac
+        while((length + pos) > (size - 1)){
+            size *= 2;
+            char *tempbuf = calloc(size,sizeof(char));
+            memset(tempbuf,'\0',size);
+            strcpy(tempbuf,*outbuf);
+            free(*outbuf);
+            *outbuf = tempbuf;
+        }
+
+        for (int j = 0; j < length; j++){					//tolko krat ho pridavam, kolko mam cisielko
+            (*outbuf)[pos] = c;
+            pos += 1;
+        }
+    }
+
+    return pos;
+}
+
+
+int mylz78decompress(char* buff,int size,char** outbuf){				//nepotrebujem pouzivat strom 
+*outbuf = calloc(size,sizeof(char));									//taka ista velkost ako vstup
+memset(*outbuf,0,size);
+char *words[MAX_WORDS];													//dvojrozmerne pole
+words[0] = "";															
+char c;
+int index = 1;
+int number;
+int pos = 0;
+int bytes_read, bytes_read_all = 0;										//citame vstupny buffer, necitame po bajtoch, viac ciferne cisla
+
+    while (sscanf(buff + bytes_read_all,"-%d-%c\n%n",&number,&c,&bytes_read) == 2){						//formatovacie citanie, pusaveme o bajty, ktore sa precitali	ak vrati ine cislo ako 2 tak je nakocni
+        bytes_read_all += bytes_read;				//o tolko sme sa posunuli
+
+        words[index] = calloc(strlen(words[number]) + 2,sizeof(char*));				//vo words sa vytvoria prefixi
+        strcpy(words[index],words[number]);											//nakopirujeme words number a pridame nakoniec c 
+        words[index][strlen(words[number])] = c;
+
+        // ak nam nebude stacit miesto v *outbuf, treba allocovat viac
+        while((strlen(words[index]) + pos) > (size - 1)){
+            size *= 2;
+            char *tempbuf = calloc(size,sizeof(char));
+            memset(tempbuf,'\0',size);
+            strcpy(tempbuf,*outbuf);
+            free(*outbuf);
+            *outbuf = tempbuf;
+        }
+
+        strcpy(*outbuf + pos,words[index]);					//nakopiruje najnovsie slovo
+        pos += strlen(words[index]);
+        index += 1;
+    }
+
+    return strlen(*outbuf);						//vratim velkost
+}
+
+
+void decompress(FILE* infile,FILE* outfile){
+fseek(infile, 0, SEEK_END);
+int insize = ftell(infile) + 1;
+rewind(infile);
+char *buffer = calloc(insize,sizeof(char));
+
+    memset(buffer,0,insize);
+    insize = fread(buffer,sizeof(char),insize - 1,infile);
+    
+    if (insize == 0){
+        assert(!ferror(infile));
+    }
+    
+    char *tempbuf = NULL;
+    int tempsize = mylz78decompress(buffer,insize,&tempbuf);				//najprv lz78
+    
+    char *outbuf = NULL;
+    int outsize = myrldecompress(tempbuf,tempsize,&outbuf);
+    
+    if (outsize > 0){
+        fwrite(outbuf,sizeof(char),outsize,outfile);
+    }
+
+    free(buffer);
+    free(tempbuf);
+    free(outbuf);
+}