Driving

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int m[100000];

int main(){
	cin.sync_with_stdio(false);
	int n,p;
	cin>>n>>p;

	for(int i=0; i<n; i++)
        cin>>m[i];

    sort(m, m+n);

    int x=m[0]-p;

    for(int i=1; i<n; i++){
        x=min(x, m[i]-p*(i+1));
    }

    cout<<m[0]-x<<endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED