Squares of a Sorted Array

Given an array of integers A sorted in non-decreasing order, return an array of the squares of each number, also in sorted non-decreasing order.

Example 1:

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Input: [-4,-1,0,3,10]
Output: [0,1,9,16,100]

Example 2:

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Input: [-7,-3,2,3,11]
Output: [4,9,9,49,121]

Note:

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    1 <= A.length <= 10000
    -10000 <= A[i] <= 10000
    A is sorted in non-decreasing order.

Solution:

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/** 
 * Forward declaration of guess API.
 * @param  num   your guess
 * @return 	     -1 if num is lower than the guess number
 *			      1 if num is higher than the guess number
 *               otherwise return 0
 * int guess(int num);
 */

public class Solution extends GuessGame {
    public int guessNumber(int n) {
        int l = 0;
        int r = n + 1;
        while (l < r) {
            int mid = l + (r - l) / 2;
            int guess = guess(mid);
            if (guess == 0) {
                return mid;
            }
            if (guess == 1) {
                l = mid;
            } else {
                r = mid + 1;
            }
        }
        return r;
    }
}