【一天一道LeetCode】#27. Remove Element

一天一道LeetCode系列

（一）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.

（二）解题

解题思路见注释

/*

在一个vector中删除指定的元素，用到erase()函数，注意迭代器会失效

erase()会返回被删除元素的下一个元素的迭代器

*/

class Solution {

public:

    int removeElement(vector<int>& nums, int val) {

        for(auto iter = nums.begin();iter!=nums.end();){

            if(*iter == val){

                iter = nums.erase(iter);//iter指向被删除元素的下一个元素

            }

            else

                ++iter;

        }

        return nums.size();

    }

};