数组题解三

移动零#283（简单）

https://leetcode.cn/problems/move-zeroes/

class Solution {
    public void moveZeroes(int[] nums) {
        //法一:双指针两次遍历.时间复杂度O(n),空间复杂度O(1)
        if (nums == null) {
            return;
        }
        int n = nums.length;
        //i是指向零的下标
        int i = 0;
        for (int j = 0; j < n; j++) {
            //第一次先用非0值填充前面的位置
            if (nums[j] != 0) nums[i++] = nums[j];
        }
        //第二次就把后面的都填充0
        for (int j = i; j < n; j++) {
            nums[j] = 0;
        }
    }
}
//=====================================================
class Solution {
    public void moveZeroes(int[] nums) {
        //法一:双指针一次遍历.时间复杂度O(n),空间复杂度O(1)
        if (nums == null) {
            return;
        }
        int n = nums.length;
        //i是指向零的下标
        int i = 0;
        for (int j = 0; j < n; j++) {
            if (nums[j] != 0) {
                int temp = nums[i];
                nums[i] = nums[j];
                nums[j] = temp;
                i++;
            }
        }
    }
}