Valid Perfect Square

Desicription

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

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

Example 1:

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Input: 16
Output: true

Example 2:

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Input: 14
Output: false

Solution

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class Solution {
public:
bool isPerfectSquare(int num) {
return int(pow(int(sqrt(num)), 2.0)) == num;
}
};