Remove Element

题目描述：

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.
解题思路：
用变量result表示目的位置的下标,result初始化为0，遍历输入数组，遇到不等于val的元素就放到result的位置，同时result加1

AC代码如下：

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