9-5每日一题：Leetcode470. 用 Rand7() 实现 Rand10()

Leetcode470. 用 Rand7() 实现 Rand10()

// The rand7() API is already defined for you.
// int rand7();
// @return a random integer in the range 1 to 7

class Solution {
public:
    int rand10() {
        int t = (rand7() - 1) * 7 + rand7();
        if (t > 40) return rand10();
        return (t - 1) % 10 + 1;
    }
};