Driving

input/code.cpp: In function 'int main()':
input/code.cpp:22:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0;i<dist.size();i++) {
                              ^

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

int main() {
    cin.sync_with_stdio(false);
    ll n, p;
    cin >> n >> p;
    vector<int> dist;

    for (ll i=0;i<n;i++) {
        ll a;
        cin >> a;
        dist.push_back(a);
    }

    sort(dist.begin(), dist.end());

    ll best = 0;

    for (int i=0;i<dist.size();i++) {
        //cout << dist[i] << endl;
        //best = max(best, p*(i+1) - i);
        best = max(best, p*(i + 1) - (dist[i] - dist[0]));
    }

    cout << best << 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