[leetcode]: 27. Remove Element

1.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.

给定一个数组nums和一个值val，去除数组中的val并返回新数组的长度。
只能在原数组上操作。

2.分析

顺序遍历一遍，用newindex来标记新数组元素的下标即可。

3.代码

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