[LeetCode] Problem 633 - Sum of Square Numbers

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

Example

No.1

Input: 5

Output: True

Explanation: 1 * 1 + 2 * 2 = 5

No.2

Input: 3

Output: False

Code

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public boolean judgeSquareSum(int c) {
    int a = 0; 
    int b = (int) Math.sqrt(c);

    while (a <= b) {
        int sum = a * a + b * b;

        if (sum < c)
            a++;
        else if (sum > c)
            b--;
        else
            return true;
    }

    return false;
}