sort_array_by_parity_II.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

/**
 * @param {number[]} A
 * @return {number[]}
 */
var sortArrayByParityII = function(A) {
  let store = { even: [], odd: [] };
  let out = [];
  for (let val of A) {
    if (val % 2 === 0) {
      store.even.push(val);
    } else {
      store.odd.push(val);
    }
  }

  for (let i = 0; i < A.length; i++) {
    if (i % 2 === 0) {
      out.push(store.even.pop());
    } else {
      out.push(store.odd.pop());
    }
  }

  return out;
};

sortArrayByParityII([4, 2, 5, 7]); //?