alternateEvenOdd.js

/* 
Given an array A of non-negative integers, half of the integers in A are odd, and half of the integers are even.

Sort the array so that whenever A[i] is odd, i is odd; and whenever A[i] is even, i is even.

You may return any answer array that satisfies this condition.

  

Example 1:

Input: [4,2,5,7]
Output: [4,5,2,7]
Explanation: [4,7,2,5], [2,5,4,7], [2,7,4,5] would also have been accepted.
 

Note:

2 <= A.length <= 20000
A.length % 2 == 0
0 <= A[i] <= 1000
*/

//Answer//
/**
 * @param {number[]} A
 * @return {number[]}
 */
var sortArrayByParityII = function(A) {
let even = A.filter(x=>x%2===0)
let odd = A.filter(x=>x%2!==0)
let B = []; 
    for (let i = 0; i <even.length ; i++) {
B.push(even[i]);
B.push(odd[i]);
} 
    return B
};