public class Solution { public int removeElement(int[] nums, int val) { if (nums == null || nums.length == 0) return 0; int left = 0; int right = nums.length - 1; while (left <= right) { while (left <= right && nums[left] != val) left++; while (left <= right && nums[right] == val) right--; if (left < right) { int tmp = nums[left]; nums[left] = nums[right]; nums[right] = tmp; } } return left; } }