LeetCode（27）——Remove Element

题目：

Given an array nums and a value val, remove all instances of that value in-place and return the new length.

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

The order of elements can be changed. It doesn't matter what you leave beyond the new length.

AC：

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