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
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<set>
#define ll long long

using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    int n,c;
    cin>>n>>c;
    vector<pair<int,int>>tab(n);
    int a,k,b;
    for(int i = 0;i<n;++i){
        cin>>a>>k;
        tab[i]={a,k};
    }
    vector<ll>best(500007,0);
    vector<ll>last_best(500007,0);
    ll best_h = 0;
    ll last_best_h = 0;
    int cur_a = 1000000;
    vector<pair<int,int>>usun;
    for(int i = n-1;i>=0;--i){
        a=tab[i].first;
        b=tab[i].second;
        if(a==cur_a){
            ll new_best = max(last_best_h+a-c,last_best[b]+a);
            if(best_h<new_best){
                best_h=new_best;
            }
            if(best[b]<new_best){
                best[b]=new_best;
                usun.push_back({b,new_best});
            }
        }
        else{
            //last_best = best;
            for(auto p : usun){
                last_best[p.first]=p.second;
            }
            usun.clear();
            last_best_h=best_h;
            cur_a=a;
            ll new_best = max(best_h+a-c,best[b]+a);
            if(best_h<new_best){
                best_h=new_best;
            }
            if(best[b]<new_best){
                best[b]=new_best;
                usun.push_back({b,new_best});
            }
        }
    }
    cout<<best_h;
    return 0;
}