For this Question: Mohit has an array of N integers containing all elements from 1 to N, somehow he lost one element from the array.
Given N-1 elements your task is to find the missing one.The first line of input contains a single integer N, the next line contains N-1 space- separated integers.

Constraints:-
1 < = N < = 100000
1 < = elements < = NPrint the missing elementSample Input:-
3
3 1

Sample Output:
2

Sample Input:-
5
1 4 5 2

Sample Output:-
3, I have written this Solution Code: 
#include <bits/stdc++.h>


using namespace std;

#define MEM(a, b) memset(a, (b), sizeof(a))

#define FOREACH(it, l) for (auto it = l.begin(); it != l.end(); it++)

#define IN(A, B, C) assert( B <= A && A <= C)

#define MP make_pair
#define FOR(i,a) for(int i=0;i<a;i++)

#define FOR1(i,j,a) for(int i=j;i<a;i++)

#define EB emplace_back

#define INF (int)1e9

#define EPS 1e-9

#define PI 3.1415926535897932384626433832795
#define max1 1001
#define MOD 1000000007

#define read(type) readInt<type>()

#define out(x) cout<<x<<'\n'
#define out1(x) cout<<x<<" "
#define END cout<<'\n'
#define int long long
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(), (v).end()
void fast(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}

signed main(){

   int n;
     cin>>n;
     int a[n];
     int sum=0;
     //map<int,int> m;
     int ans = n*(n+1);
     ans/=2;
     FOR(i,n-1){
     cin>>a[i];
     sum+=a[i];
     //m[a[i]]++;
     }
     out(ans-sum);
}
, In this Programming Language: C++, Now tell me if this Code is compilable or not?