Codeforces Round 627 (Div. 3) 1324D. Pair of Topics Solution

                               

  Problem Link : https://codeforces.com/contest/1324/problem/D

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. int32_t main() {
10. ios_base::sync_with_stdio(0);
11. cin.tie(0);
12. int n ;
13. cin >> n ;
14. int a[n+1],b[n+1] ;
15. vector<int > c(n);
16. for ( int i = 0 ; i < n ; i++ ) cin >> a[i] ;
17. for ( int i = 0 ; i < n ; i++ ) cin >> b[i] ;
18. for ( int i = 0 ; i < n ; i++ ) {
19. c[i] = a[i] - b[i] ;
20. }
21. sort (c.begin() , c.end()) ;
22. long long ans = 0 ;
23. for ( int i = 0 ; i < n ; i++ ) {
24. if (c[i] > 0){
25. int pos = lower_bound(c.begin(),c.end(),-c[i]+1)-c.begin() ;
26. ans += (i - pos);
27. }
28. else
29. continue ;
30. }
31. cout << ans << endl;
32. return 0;
33. }