uva11192.c

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

int main() {
    int g;
    while (scanf("%d", &g)) {
        if (g == 0) break;

        char input[110];
        scanf("%s", input);

        int len = strlen(input);
        int width = len / g;

        int i;
        for(i=0; i<len; i+=width) {
            int j;
            for(j=0; j<width/2; j++) {
                /* swap input[i+j], input[i+width-1-j]*/
                char temp = input[i+j];
                input[i+j] = input[i+width-1-j];
                input[i+width-1-j] = temp;
            }

        }

        printf("%s\n", input);
    }
    return 0;
}