Given an array nums and a value val, 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 by modifying the input array in-place with O(1) extra memory. The order of e

test.cpp

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