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Valid Perfect Square - Math - Easy - LeetCode - MiniTV

Valid Perfect Square - Math - Easy - LeetCode - मिनी टीवी

Given a positive integer num, write a function that returns True if num is a perfect square else False.

Follow up: Do not use any built-in library function such as sqrt.

 

Example 1:

Input: num = 16
Output: true
Example 2:

Input: num = 14
Output: false
 

Constraints:

1 <= num <= 2^31 - 1

public class Solution {
    public bool IsPerfectSquare(int num) {
        int i = 1;
        int sum = 0;
        while (sum < num) {
            sum += i;
            if(sum<0){
                return false;
            }
            i += 2;
        }
        return sum==num;
    }
}

Time Complexity: O(n)

Space Complexity: O(1)