leetcode_977

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:

Input: [-4,-1,0,3,10] Output: [0,1,9,16,100] Example 2:

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

Note:

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

Solutions

1. merge sorted list

class Solution {
public:
    vector<int> sortedSquares(vector<int>& A) {
        if (!A.size()) return {};
        vector<int> res(A.size());
        int i = 0, j = A.size() - 1, w = j;

        while (w >= 0) {
            if (abs(A[j]) > abs(A[i]))
                res[w--] = pow(A[j--], 2);
            else
                res[w--] = pow(A[i++], 2);
        }

        return res;
    }
};

or

class Solution {
public:
    vector<int> sortedSquares(vector<int>& A) {
        vector<int> res(A.size());
        int i = 0, j = A.size() - 1, w = j;

        while (w >= 0) {
            res[w--] = abs(A[i]) > abs(A[j]) 
                ? pow(A[i++], 2) 
                : pow(A[j--], 2);
        }

        return res;
    }
};