LeetCode367. Valid Perfect Square判断是否为完全平方数 #算法# 第十二周

Input: 16
Output: true

Input: 14
Output: false

class Solution {
public:
    bool isPerfectSquare(int num) {
        int rest = num % 10;
        if(rest == 2 || rest == 3 || rest == 7 || rest == 8)
            return false;
        int sum = 0;
        for(int i = 1; sum < num; i = i + 2){
            sum += i;
            if(sum == num)
                return true;
        }
        return false;
    }
};