283. Move Zeroes

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Total Accepted: 131094
Total Submissions: 279468
Difficulty: Easy
Contributors: Admin

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.
For example, given nums = [0, 1, 0, 3, 12]
, after calling your function, nums
should be [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.

Credits:Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

 // Shift non-zero values as far forward as possible
    // Fill remaining space with zeros
    // ref: https://discuss.leetcode.com/topic/24716/simple-o-n-java-solution-using-insert-index
    public void moveZeroes(int[] nums) {
       if (nums == null || nums.length == 0) return;        
    
        int insertPos = 0;
        for (int num: nums) {
            if (num != 0) nums[insertPos++] = num;
        }        
    
        while (insertPos < nums.length) {
            nums[insertPos++] = 0;
        }
    }
    
    public void moveZeroesFailed(int[] nums) {
        for (int i = 1; i < nums.length; i++) {
            if (nums[i - 1] == 0) {
                swap(nums, i - 1, i);
            }
        }
     
    }
    
    public void swap(int[] nums, int j, int k) {
        int temp = nums[j];
        nums[j] = nums[k];
        nums[k] = temp;
    }