Sort Array By Parity II

Description

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:

1. 2 <= A.length <= 20000
2. A.length % 2 == 0
3. 0 <= A[i] <= 1000

 

Solution(javascript)

// 两个指针分别找不满足的情况，然后交换，类似905
const sortArrayByParityII = function (A = []) {
  let index1 = 0
  let index2 = 1
  while (index1 < A.length && index2 < A.length) {
    while (A[index1] % 2 === 0) {
      index1 += 2
    }
    while (A[index2] % 2 === 1) {
      index2 += 2
    }
    if (index1 < A.length && index2 < A.length) {
      const temp = A[index1]
      A[index1] = A[index2]
      A[index2] = temp
    }
  }
  return A
}