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
#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
#include <set>

using namespace std;


int main() {
    int n, c, size, color;
    cin >> n >> c;
    long long int global_max = 0, temp_global_max = 0;
    vector<long long int> max_ending_with_color(500001, 0);

    vector<set<int>> available_colors_for_size(500001);

    for (int i = 1; i <= n; i++) {
        cin >> size >> color;
        available_colors_for_size[size].insert(color);

    }
    n = 500000;

    // for (int i = 1; i <= n; i++) {
    //     cout << i << ": ";
    //     for (set<int>::iterator it = available_colors_for_size[i].begin(); it != available_colors_for_size[i].end(); ++it) {
    //         cout << *it << " ";
    //     }
    //     cout << endl;
    // }

    // for (int i = 1; i <= n; i++) {
    //     cout << max_ending_with_color[i] << " ";
    // }
    // cout << endl;

    for (int size = 1; size <= n; size++) {
        for (set<int>::iterator it = available_colors_for_size[size].begin(); it != available_colors_for_size[size].end(); ++it) {
            int color = *it;
            long long int val = max(global_max - c + size, max_ending_with_color[color] + size);
            temp_global_max = max(temp_global_max, val);
            max_ending_with_color[color] = val;
        }

        // for (int i = 1; i <= 10; i++) {
        //     cout << max_ending_with_color[i] << " ";
        // }
        // cout << endl;

        global_max = temp_global_max;
    }

    cout << global_max << endl;

    return 0;
}