633. Sum of Square Numbers

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LeetCode

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Problem

Given a non-negative integer c, decide whether there’re two integers a and b such that $a^2 + b^2 = c$.

Example 1:

Input: c = 5
Output: true
Explanation: 1 * 1 + 2 * 2 = 5

Example 2:

Input: c = 3
Output: false

Constraints:

• $0 <= c <= 2^{31} - 1$

Code

class Solution {
    public boolean judgeSquareSum(int c) {
        long left = 0;
        long right = (long) Math.sqrt(c);

        while (left <= right) {
            long curr = left * left + right * right;

            if(curr == c) return true;

            if (curr < c) {
                left++;
            } else if (curr > c) {
                right--;
            } 
        }

        return false;
    }
}