牛客网：NC151 最大公约数

暴力

import java.util.*;


public class Solution {
    
    public int gcd (int a, int b) {
        // write code here
        int c = Math.min(a, b);
        if (a % b == 0) return b;
        if (b % a == 0) return a;
        int res = 1;
        for (int i = 2; i <= c; i++){
            if (a % i == 0 && b % i == 0){
                res = i;
            }
        }
        return res;
    }
}

辗转相除法

import java.util.*;


public class Solution {
    
    public int gcd (int a, int b) {
        // write code here
       if ( a % b == 0) return b;
       else return gcd (b, a % b);
    }
}