Codeforces Round #837 (Div. 2) 1771B. Hossam and Friends Solution

 

 Problem Link: https://codeforces.com/problemset/problem/1771/B

Solution in C++:

1. /// La ilaha illellahu muhammadur rasulullah
2. ///******Bismillahir-Rahmanir-Rahim******///
3. /// Abul Hasnat Tonmoy
4. /// Department of CSE,23rd batch
5. /// Islamic University,Bangladesh
6. ///**********ALLAH IS ALMIGHTY************///
7. #include <bits/stdc++.h>
8. using namespace std;
9. #define ll long long int
10. int main() {
11. ios_base::sync_with_stdio(0);
12. cin.tie(0);
13. ll t;
14. cin >> t;
15. while (t--) {
16. ll n, m, x, y, ans = 0;
17. cin >> n >> m;
18. std::vector<ll> v(n + 1, -1);
19. while (m--) {
20. cin >> x >> y;
21. if (x > y) swap(x, y);
22. v[y] = max(v[y], x);
23. }
24. ll next = 1;
25. for (ll i = 1; i <= n; i++) {
26. next = max(next, v[i] + 1);
27. ans += (i - next + 1);
28. }
29. cout << ans << endl;
30. }
31. }