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; } };