LeetCode-面试题21-调整数组顺序使奇数位于偶数前面

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 {
    public int[] exchange(int[] nums) {
        if(nums==null||nums.length==0){
            return nums;
        }
        int start = 0;
        int end = nums.length-1;
        while(start<end){
            // 当前是奇数时，向后移动start，直到碰到偶数
            while(start<end&&(nums[start]&0x1)!=0)
                start++;
            // 当前是偶数时，向前移动end，直到碰到奇数
            while(start<end&&(nums[end]&0x1)==0)
                end--;
            // 当start和end是前偶后奇时，交换2个数位置
            if(start<end){
                int temp = nums[start];
                nums[start] = nums[end];
                nums[end] = temp;
            }
        }
        return nums;
    }
}

class Solution:
    def exchange(self, nums: List[int]) -> List[int]:
        if not nums or len(nums)==0:
            return nums;
        start ,end = 0, len(nums)-1
        while start<end:
            while start<end and (nums[start]&0x1)!=0:
                start +=1
            while start<end and (nums[end]&0x1)==0:
                end -=1
            if start<end:
                temp = nums[start]
                nums[start] = nums[end]
                nums[end] = temp
        return nums