1. Remove Element My Submissions QuestionEditorial Solution
   
   Total Accepted: 115367 Total Submissions: 340963 Difficulty: Easy
   
   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：如下，一碰到指定的val，dis++，dis代表当前元素非val得时候向前移动的距离

class Solution {

public:

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

        int n=nums.size();

        int i=0,dis=0;

        while(i<n){

            if(nums[i]==val)dis++;

            else nums[i-dis]=nums[i];

            i++;

        }

        return n-dis;

    }

};