ZOJ的1003的不同解法，其中一个能AC，而另一个输出错误。因此，我用自己的计算机产生随机数对（100000次以上），结果就是两个程序输出一样，并没有错，我该咋办？
可以通过的：
#include <stdio.h>
int flag1, flag2;

void dfs(int n, int m, int fac){
    if (flag1)
        return;
    if (n == 1 && m == 1){
        flag1 = 1;
        flag2 = 1;
        return;
    }
    if (m == 1){
        flag2 = 1;
    }

    if (fac < 2)
        return;
    if (n % fac == 0)
        dfs(n / fac, m, fac - 1);
    if (m % fac == 0)
        dfs(n, m / fac, fac - 1);
    dfs(n, m, fac - 1);
}

int main(){
    int n, m;
    while(~scanf("%d%d", &n, &m)){
        if (m > n){
            n = m ^ n;
            m = m ^ n;
            n = m ^ n;
        }
        flag1 = 0;
        flag2 = 0;
        dfs(n, m, 100);
        if (flag1 || !flag2)
            printf("%d\n", n);
        else
            printf("%d\n", m);
    }
    return 0;
}

不能通过的：
#include <stdbool.h>
#include <stdio.h>

#define MAX 100

bool factorFlag[MAX];

bool isResolve(int n, int factor){
    if (n == 1)
        return true;
    if (factor < 2)
        return false;
    else{
        while (factor >= 2){
            if (factorFlag[factor-1] == false && n % factor == 0)
                break;
            else
                factor--;
        }
        if (factor < 2)
            return false;
        if(isResolve(n/factor, factor-1))
            return true;
        else
            return isResolve(n, factor-1);
    }
}

bool isFactor(int n, int m, int factor){
    if (n == 1)
        return isResolve(m, MAX);
    if (factor < 2)
        return false;
    while (factor >= 2){
        if (n % factor == 0)
            break;
        else
            factor--;
    }
    if (factor < 2)
        return false;
    factorFlag[factor-1] = true;
    if (isFactor(n / factor, m, factor-1))
        return true;
    factorFlag[factor-1] = false;
    return isFactor(n, m, factor-1);
}

int main(){
    int i = 0;
    while (i < MAX){
        factorFlag[i++] = false;
    }
    int a, b;
    while (~scanf("%d%d", &a, &b)){
        if (b > a){
            b = a ^ b;
            a = a ^ b;
            b = a ^ b;
        }
        if (!isResolve(b, MAX) && b > MAX){
            printf("%d\n", a);
        }
        else if (isFactor(a, b, MAX))
            printf ("%d\n", a);
        else
            printf("%d\n", b);
    }
    return 0;
}