結果

問題 No.898 tri-βutree
コンテスト
ユーザー tonyu0
提出日時 2019-10-25 10:46:17
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 240 ms / 4,000 ms
コード長 2,385 bytes
コンパイル時間 1,323 ms
コンパイル使用メモリ 109,268 KB
実行使用メモリ 34,560 KB
最終ジャッジ日時 2024-11-08 23:09:17
合計ジャッジ時間 6,723 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 21
権限があれば一括ダウンロードができます
コンパイルメッセージ
In member function 'int LCA<T>::get_lca(int, int) [with T = long long int]',
    inlined from 'T LCA<T>::get_length(int, int) [with T = long long int]' at main.cpp:73:20,
    inlined from 'int main()' at main.cpp:103:52:
main.cpp:58:17: warning: 'v3' may be used uninitialized [-Wmaybe-uninitialized]
   58 |     if(depth[x] > depth[y]) swap(x, y);
main.cpp: In function 'int main()':
main.cpp:94:27: note: 'v3' was declared here
   94 |     int dep = -1, v1, v2, v3, a;
      |                           ^~
In member function 'int LCA<T>::get_lca(int, int) [with T = long long int]',
    inlined from 'T LCA<T>::get_length(int, int) [with T = long long int]' at main.cpp:73:20,
    inlined from 'int main()' at main.cpp:103:27:
main.cpp:58:17: warning: 'v2' may be used uninitialized [-Wmaybe-uninitialized]
   58 |     if(depth[x] > depth[y]) swap(x, y);
main.cpp: In function 'int main()':
main.cpp:94:23: note: 'v2' was declared here
   94 |     int dep = -1, v1, v2, v3, a;
      |                       ^~
In member function 'int LCA<T>::get_lca(int, int) [with T = long long int]',
    inlined from 'T LCA<T>::get_length(int, int) [with T = long long int]' at main.cpp:73:20,
    inlined from 'int main()' at main.cpp:103:27:
main.cpp:58:17: warning: 'v1' may be used uninitialized [-Wmaybe-uninitialized]
   58 |     if(depth[x] > depth[y]) swap(x, y);
main.cpp: In function 'int main()':
main.cpp:94:19: note: 'v1' was declared here
   94 |     int dep = -1, v1, v2, v3, a;
      |                   ^~

ソースコード

diff # 

#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <iomanip>
#include <cmath>
#include <map>
using namespace std;
#define REP(i,n) for (int i=0;i<(n);++i)
#define rep(i,a,b) for(int i=a;i<(b);++i)
using ll = long long;
constexpr ll INF = 1LL << 60;
constexpr int MOD = 998244353;

struct Edge {
  int src, dst, cost;
  Edge(int s, int d, int c = 1) : src(s), dst(d), cost(c) {}
  bool operator<(const Edge &e){ return cost < e.cost;}
};
using Edges = vector<Edge>;
using Graph = vector<Edges>;

// build O(NlogN), query O(logN)
template<typename T>
struct LCA {
  vector<T> cost;
  vector<int> depth;
  vector<vector<int>> par;
  Graph g;
  int logn;

  LCA(int n, Graph g) : cost(n), depth(n), g(g) {
    logn = 0;
    while((1<<logn) < n) ++logn;

    par.assign(n+1, vector<int>(logn, n));
    dfs(0, -1, 0, 0);

    for(int i = 0; i < logn-1; ++i) {
      for(int v = 0; v < n; ++v) {
        par[v][i+1] = par[par[v][i]][i];
      }
    }
  }

  void dfs(int v, int p, int d, T c) {
    if(p != -1) par[v][0] = p;
    depth[v] = d;
    cost[v] = c;

    for(Edge e : g[v]) {
      if(e.dst == p) continue;
      dfs(e.dst, v, d+1, cost[v] + e.cost);
    }
  }

  int get_lca(int x, int y) {
    if(depth[x] > depth[y]) swap(x, y);

    for(int i = logn-1; i >= 0; --i) {
      if(((depth[y] - depth[x])>>i) & 1) y = par[y][i];
    }
    if(x == y) return y;

    for(int i = logn-1; i >= 0; --i) {
      int nx = par[x][i], ny = par[y][i];
      if(nx != ny) x = nx, y = ny; 
    }
    return par[y][0];
  }

  T get_length(int x, int y) {
    int z = get_lca(x, y);
    return cost[x] + cost[y] - cost[z] * 2;
  }
};

ll q, n, k, u, v, w;

int main() {
  cin.tie(0); ios_base::sync_with_stdio(false); 
  cin >> n;
  Graph g(n);
  REP(i, n-1) {
    cin >> u >> v >> w;
    g[u].emplace_back(u, v, w);
    g[v].emplace_back(v, u, w);
  }
  LCA<ll> lca(n, g);

  cin >> q;
  REP(i, q) {
    cin >> u >> v >> w;
    int dep = -1, v1, v2, v3, a;
    
    a = lca.get_lca(u, v);
    if(lca.depth[a] > dep) v1 = u, v2 = v, v3 = w, dep = lca.depth[a];
    a = lca.get_lca(v, w);
    if(lca.depth[a] > dep) v1 = v, v2 = w, v3 = u, dep = lca.depth[a];
    a = lca.get_lca(w, u);
    if(lca.depth[a] > dep) v1 = w, v2 = u, v3 = v, dep = lca.depth[a];

    cout << lca.get_length(v1, v2) + lca.get_length(lca.get_lca(v1, v2), v3) << '\n';
  }
  return 0;
}
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