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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. // Speed
  5. #define fast_io ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
  6.  
  7. // Typedefs
  8. #define int long long
  9. #define pb push_back
  10. #define ff first
  11. #define ss second
  12. #define all(x) (x).begin(), (x).end()
  13. #define rall(x) (x).rbegin(), (x).rend()
  14. #define sz(x) ((int)(x).size())
  15. #define endl '\n'
  16. #define yes cout << "yes\n"
  17. #define no cout << "no\n"
  18.  
  19. // Loops
  20. #define rep(i,a,b) for(int i=a;i<b;++i)
  21. #define per(i,a,b) for(int i=b-1;i>=a;--i)
  22. #define each(x, a) for (auto& x : a)
  23.  
  24. // Consts
  25. const int INF = 1e18;
  26. const int MOD = 1e9+7;
  27. const int N = 2e5 + 5;
  28.  
  29. // Math
  30. int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
  31. int lcm(int a, int b) { return (a / gcd(a, b)) * b; }
  32.  
  33. int power(int a, int b, int m = MOD) {
  34.     int res = 1;
  35.     while (b > 0) {
  36.         if (b & 1) res = res * a % m;
  37.         a = a * a % m;
  38.         b >>= 1;
  39.     }
  40.     return res;
  41. }
  42.  
  43. int modinv(int a, int m = MOD) {
  44.     return power(a, m - 2, m);
  45. }
  46.  
  47. // Logic
  48. void solve() {
  49.     int n;
  50.     cin >> n;
  51.  
  52.     vector<pair<int, int>> a(n);
  53.     rep(i, 0, n) cin >> a[i].ff >> a[i].ss;
  54.  
  55.     vector<int> parent(N);
  56.     iota(all(parent), 0);
  57.  
  58.     auto find = [&](int x) {
  59.         while (x != parent[x]) x = parent[x] = parent[parent[x]];
  60.         return x;
  61.     };
  62.  
  63.     auto unite = [&](int x, int y) {
  64.         x = find(x);
  65.         y = find(y);
  66.         if (x != y) parent[y] = x;
  67.     };
  68.  
  69.     set<int> covered;
  70.  
  71.     each(p, a) {
  72.         int u = p.ff, v = p.ss;
  73.         if (find(u) != find(v)) {
  74.             unite(u, v);
  75.             int l = min(u, v);
  76.             int r = max(u, v);
  77.             rep(i, l, r + 1) covered.insert(i);
  78.         }
  79.     }
  80.  
  81.     cout << sz(covered) << endl;
  82. }
  83.  
  84. // Main
  85. int32_t main() {
  86.     fast_io;
  87.  
  88.     int t;
  89.     cin >> t;
  90.     while (t--) {
  91.         solve();
  92.     }
  93.  
  94.     return 0;
  95. }
Success #stdin #stdout 0.01s 5304KB
comments (?)
stdin 
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stdout 
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https://ideone.com/dJc7HF
language:
C++ (gcc 8.3)
created:
2 days ago
visibility:
public

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