27. Remove Element 难度：easy

题目：

Given an array and a value, 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 in place with constant memory.

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

Example:
Given input array nums = [3,2,2,3], val = 3

Your function should return length = 2, with the first two elements of nums being 2.

思路：

对数组进行一次遍历，删除与给定值相等的关键字，返回新长度即可。

程序：

class Solution {public:    int removeElement(vector<int>& nums, int val) {        int i = 0 , k = 0;        while (i < nums.size())        {            if (nums[i] != val)                nums[k++] = nums[i];            i++;        }        return k;    }};