gcd求最大公约数

gcd（M，N） = 1. M%N = 0 : N
2. M%N=R, R>0 : gcd(N, R)
这里不做过多解释。

int ggcd[100][100];

int gcd(int M, int N)
{
    if(ggcd[M][N] != 0)
        return ggcd[M][N];

    int R = M%N;
    if(R == 0)
        return N;
    else
    {
        if(R > 0)
        {
            int gg = gcd(N, R);
            ggcd[N][R] = gg;    //这里多点多余，会进行重复赋值
            ggcd[M][N] = gg;
            return gg;
        }
    }

    return -1;
}


int main(int argc, char *argv[])
{
    
    int t = gcd(78,16);

    int i,j;
    for(i = 0; i < 100; i++)
        for(j = 0; j < 100; j++)
        {
            if(ggcd[i][j] != 0)
                printf("%d and %d is %d\n",i,j,ggcd[i][j]);
        }

    printf("%d\n",t);
}