LeetCode283 Move Zeroes

题目：

       Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements.

       Example:

              Input: [0,1,0,3,12]

       Output: [1,3,12,0,0]

       Note:

              You must do this in-place without making a copy of the array.

              Minimize the total number of operations.

public class MoveZero {
    public static void moveZeroes(int[] nums) {
        int k = 0;//nums, [0...k)中元素均为非0
        //遍历第i个元素后保证nums[0...i]中所有非零元素都按照顺序排列在[0...k]中,同时[k...i]为0
        for (int i = 0; i < nums.length; i++) {
            if (nums[i] != 0)
                if(i != k)
                    swap(nums, k++, i);
                else//i==k
                    k++;
        }
    }

    public static void swap(int [] arr, int i , int j){
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static void main(String[] args) {
        int[] nums = {0,1,0,3,12};
        moveZeroes(nums);
        System.out.println(Arrays.toString(nums));
    }
}