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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define F first
  5. #define S second
  6. #define pb push_back
  7. #define all(a) a.begin(), a.end()
  8.  
  9. typedef long long ll;
  10. typedef pair<int, int> ii;
  11.  
  12. const int N = 100000 + 5;
  13.  
  14. vector<ii> g[N];
  15. int n, s;
  16. long long maxPath = 0;
  17. long long sumPath = 0;
  18.  
  19. void dfs(int u, int p, long long sum)
  20. {
  21.     maxPath = max(maxPath, sum);
  22.     for(ii &x : g[u]) 
  23.         if(x.F != p) dfs(x.F, u, sum + x.S);
  24. }
  25.  
  26. void solve()
  27. {
  28.     cin >> n >> s;
  29.     for(int i = 1; i < n; i++)
  30.     {
  31.         int u, v, w;
  32.         cin >> u >> v >> w;
  33.         g[u].pb({v, w});
  34.         g[v].pb({u, w});
  35.         sumPath += w;
  36.     }
  37.     dfs(s, 0, 0);
  38.     cout << sumPath * 2 - maxPath;
  39. }
  40.  
  41. signed main()
  42. {
  43.     cin.tie(0)->sync_with_stdio(0);
  44.     int t = 1;
  45.     // cin >> t;
  46.     while(t--) solve();
  47.     return 0;
  48. }
Success #stdin #stdout 0.01s 5788KB
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stdout 
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https://ideone.com/4gFnaO
language:
C++14 (clang 8.0)
created:
2 years ago
visibility:
public

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