CodeForces Problem 862A - Mahmoud and Ehab and the MEX Solution (C++)

Problem:

Please find the problem here.

Solution:

This is the simplest problem I ever had, just implement the given formulas! However, it does take me some time to write.

Explanation:

1.MEX has two condition

2.MEX equal to entered input ... MEX will increase by 1 as element is erased.

3.MEX less than input...MEX will decline as element is inserted before MEX

4.Goodluck!

Code:

#include<bits/stdc++.h>

#define FOR(i,n) for(int i=0;i<n;i++)

using namespace std;

main(){

int n;

int k;

int x;

cin>>n>>k;

int ans=k;

FOR(i,n){

cin>>x;

if(x<k){

ans--;

}

else if(x==k){

ans++;

}

}

cout<<ans;

}