输入：nums = [1,2,3,4]
输出：[1,3,2,4] 
注：[3,1,2,4] 也是正确的答案之一。

class Solution:
    def exchange(self, nums: List[int]) -> List[int]:
        head = 0
        wei = len(nums)-1
        li = [0]*(wei+1)
        for i in nums:
            if i%2==0:
                li[wei] = i
                wei-=1
            else:
                li[head] = i
                head+=1
        return li

public class Solution {
    public int[] Exchange(int[] nums) {
        int head= 0;
        int wei = nums.Length-1;
        int[] ans = new int[wei+1];
        foreach (int i in nums){
            if (i%2!=0) {
                ans[head] = i;
                head++;
            }
            else {
                ans[wei] = i;
                wei--;
            }
        }
        return ans;
    }
}