C++ | Leetcode C++题解之第202题快乐数

题目：

题解：

class Solution {
public:int ProductSum(int n){int sum = 0;while(n){int temp = n % 10;sum += temp*temp;n /= 10;}return sum;}bool isHappy(int n) {int slow = n,fast = n;// 快慢指针，找环的相遇位置do{slow = ProductSum(slow);fast = ProductSum(ProductSum(fast));}while(slow != fast);// 如果相遇时是 1 就是快乐数return slow == 1;}
};