[leetcode] 922. 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

分析

题目的意思是：这道题是说奇数位置就放奇数，偶数位置放偶数，我这里动手实现了自己的版本，只遍历了一遍，应该是最优的了。跟标准答案的思路比较接近，我这里就分享一下我自己的实现方案了。

代码

class Solution:
    def sortArrayByParityII(self, A: List[int]) -> List[int]:
        i=0
        j=1
        n=len(A)
        while(i<n and j<n):
            while(i<n and i%2==0 and A[i]%2==0):
                i+=2
            while(j<n and j%2==1 and A[j]%2==1):
                j+=2
            if(i<n and j<n):
                A[i],A[j]=A[j],A[i]
        return A

参考文献

​​[LeetCode]Approach 2: Read / Write Heads​​