1110B - Tape - CodeForces Solution

#include<bits/stdc++.h>
#define ll long long
#define no cout<<"NO\n";
#define yes cout<<"YES\n";
using namespace std;
int main()
{
    ios_base::sync_with_stdio(NULL);
	cin.tie(0); cout.tie(0);
	int n,m,k,x,z,q;
	cin>>n>>m>>k;
	q=n;
	vector<int>v;
	cin>>x;
	z=x;
	n--;
	while(n--)
    {
        cin>>x;
        v.push_back(x-z-1);
        z=x;
    }
    sort(v.begin(),v.end());
    ll ans=0;
    for(int i=0;i<q-k;++i)ans+=v[i];
    cout<<ans+q;
}