[LeetCode27]Remove Element

题目：

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

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

思路：设置两个变量start和end同时从前后向中间遍历，遇到等于val的元素则交换数组end和start位置的值，直到end==start

代码：

public class Solution {
    public int RemoveElement(int[] nums, int val) {
        int start = 0;
        int end = nums.Length;
        if(end == 0)
            return 0;
        while(start < end)
        {
            if(nums[start] == val)
            {
                int temp = nums[start];
                nums[start] = nums[end-1];
                nums[end-1] = temp;
                end--;
            }
            else
            {
                start++;
            }
        }
        return end;
    }
}