1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
#include <bits/stdc++.h>
using namespace std;

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	
	long long n, c; cin >> n >> c;
	vector <pair <long long, long long>> a(n + 1, {-1, -1});
	for (long long i = 1; i <= n; ++i) {
		cin >> a[i].first >> a[i].second;
	}
	
	reverse(a.begin(), a.end());
	vector <pair <long long, long long>> b;
	b.push_back(a[0]);
	for(int i = 1; i < n; i++) {
		if(a[i].first != a[i-1].first || a[i].second != a[i].second) {
			b.push_back(a[i]);
		}
	}
	b.push_back({-1, -1});
	n = b.size();
	a = b;
	unordered_map <long long, long long> m;
	long long best = 0, best_same = 0;
	long long score = 0;
	for (long long i = 0; i < n; ++i) {
		m[a[i].second] = a[i].first + max(m[a[i].second], best - c);
		best_same = max(best_same, m[a[i].second]);
		if(a[i].first != a[i + 1].first) best = max(best, best_same);
		score = max(score, best);
	}
	
	cout << score << "\n";
}