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
36
37
38
39
40
41
42
43
44
#include <bits/stdc++.h>
typedef long long ll;
using namespace std;

constexpr ll M = 500'010;

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	
	ll n, c;
	cin >> n >> c;
	vector<pair<ll, ll>> klocki(n);
	for(ll i=0; i<n; ++i) cin >> klocki[i].first >> klocki[i].second;
	vector<ll> last(M, -1);
	vector<ll> dp(n);
	ll maximum = -1;
	queue<pair<ll, ll>> Q;
	for(ll i=0; i<n; ++i) {
		auto[w, k] = klocki[i];
		while(!Q.empty()) {
			auto[kolor, idx] = Q.front();
			if(klocki[idx].first < w) {
				if(maximum == -1) maximum = idx;
				else if(dp[maximum] < dp[idx]) maximum = idx;
				last[kolor] = idx;
				Q.pop();
			} else break;
		}
		dp[i] = w;
		if(last[k]!=-1) {
			dp[i] = max(dp[i], w+dp[last[k]]);
		}
		if(maximum != -1) {
			dp[i] = max(dp[i], w+dp[maximum] - (klocki[maximum].second != k)*c);
		}
		Q.push({k, i});
	}
	ll ans = dp[0];
	for(int i=1; i<n; ++i) ans=max(ans, dp[i]);
	cout << ans << "\n";
	
	return 0;
}