LeetCode 470 用Rand7()实现Rand10()[数学] HERODING的LeetCode之路

Posted 2021-09-19 HERODING23

解题思路：
实现起来其实非常简单，就是保证十个数范围内的数的概率相等，代码如下：

// 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 row, col, idx;
        do {
            row = rand7();
            col = rand7();
            idx = col + (row - 1) * 7;
        } while (idx > 40);
        return 1 + (idx - 1) % 10;
    }
};