AdventOfCode4.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(){
        
        int good = 0;
        FILE *fp = fopen("input.txt","r");
        char str[4092];
  
        while (fgets(str, sizeof str, fp) != NULL){

        const char brk[] = " \n";
        /* strtok breaks when either " " or "\n" is encountered hence they can
         * be clubbed together.
         * fgets() reads the string + \n, which is why breakpoint is " " and 
         * "\n", otherwise it will read the not needed \n.  
         */
        

        char *token;
        int count = 0;
        int flag = 0;
        char *list[30];
        
        token = strtok(str,brk);
        list[0] = token;
        
        for ( int i = 1 ; token != NULL ; i++){
                token = strtok(NULL, brk);
                ++count;
                list[i] = token;
        
        }

        for( int i = 0 ; i < count ; i++ ){
                for ( int k = i+1 ; k < count ; k++){
                        if ( strcmp(list[k],list[i]) == 0 )
                               ++flag;
                }
        }

                if (flag == 0 )good++; 
        }

        fclose(fp);
        printf("%d",good);
        return 0;

}