ACM 488 Triangle Wave

#include <stdio.h>

int main(void)
{
    int n, a, f, i, j;
   
    scanf("%d", &n);
    while (n--)
    {
        scanf("%d%d", &a, &f);
        while (f--)
        {
            for (i = 1; i <= a; i++)
            {
                for (j = 0; j < i; j++)
                    printf("%d", i);
                puts("");
            }
            for (i-=2; i > 0; i--)
            {
                for (j = 0; j < i; j++)
                    printf("%d", i);
                puts("");
            }
            if (f)
                puts("");
        }
        if (n)
            puts("");
    }
   
    return 0;
}