Move Zeroes

Solution:

1. From left to right

class Solution {
    public void moveZeroes(int[] nums) {
        if (nums == null || nums.length < 2) {
            return;
        }
        
        int zeroIndex = 0, nonZeroIndex = 0, n = nums.length;
        while (nonZeroIndex < n) {
            while (zeroIndex < n && nums[zeroIndex] != 0) {
                zeroIndex++;
            } 
            
            while (nonZeroIndex < n && nums[nonZeroIndex] == 0) {
                nonZeroIndex++;
            }
            
            if (nonZeroIndex == n || zeroIndex == n) {
                return;
            }
            
            if (zeroIndex < nonZeroIndex) {
                int temp = nums[zeroIndex];
                nums[zeroIndex] = nums[nonZeroIndex];
                nums[nonZeroIndex] = temp;
            }
            nonZeroIndex = zeroIndex + 1;
        }
    }
}

class Solution {
    public void moveZeroes(int[] nums) {
        if (nums == null || nums.length < 2) {
            return;
        }
        
        int index = 0, n = nums.length;
        for (int i = 0; i < n; i++) {
            if (nums[i] != 0) {
                nums[index++] = nums[i];
            }
        }
        
        while (index < n) {
            nums[index++] = 0;
        }
    }
}