CodinGame_2023_08_22__13_23_04__n_chars.c

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

/**
 * Auto-generated code below aims at helping you parse
 * the standard input according to the problem statement.
 **/

char *substr(char const *input, size_t start, size_t len) {
    char *ret = malloc(len+1);
    memcpy(ret, input+start, len);
    ret[len]  = '\0';
    return ret;
}

int main()
{
    int N;
    scanf("%d", &N); fgetc(stdin);
    char TEXT[1000];
    scanf("%[^\n]", TEXT);

    for (int i=0; TEXT[i] != '\0'; i++) {
        char *s = substr(TEXT, i, N);
        printf("%s\n", s);
        if (i+N==strlen(TEXT)) break;
        free(s);
    }

    return 0;
}