Submission #51220

#	Time	Username	Problem	Language	Result	Execution time	Memory
51220		BrunoPloumhans	Sightseeing (NOI14_sightseeing)	C++14	25 / 25	2886 ms	275048 KiB

sightseeing

#include <bits/stdc++.h>
using namespace std;

#define int long long

struct UnionFind {
  vector<int> p, ranks;

  UnionFind(int n) : p(n), ranks(n, 0) {
    for(int i = 0; i < n; ++i) {
      p[i] = i;
    }
  }

  int find_set(int a) {
    return p[a] == a ? a : p[a] = find_set(p[a]);
  }

  bool is_same_set(int a, int b) {
    return find_set(a) == find_set(b);
  }

  void unite(int a, int b) {
    int x = find_set(a), y = find_set(b);
    if(x != y) {
      if(ranks[x] > ranks[y]) {
	p[y] = x;
      } else {
	p[x] = y;
	if(ranks[x] == ranks[y]) {
	  ++ranks[y];
	}
      }
    }
  }
};

typedef pair<int, pair<int, int>> iii;

struct edge {
  int v, w;
};

vector<vector<edge>> adj;

vector<int> dist;

void dfs(int u, int p = -1, int d = 1e9) {
  dist[u] = d;
  for(edge e : adj[u]) {
    if(e.v != p) {
      dfs(e.v, u, min(d, e.w));
    }
  }
}

signed main() {
  cin.sync_with_stdio(false);
  cin.tie(0);
  int v, e, q;
  cin >> v >> e >> q;
  adj.resize(v);
  dist.resize(v);
  vector<iii> edges(e);
  for(int i = 0; i < e; ++i) {
    int a, b, c;
    cin >> a >> b >> c;
    --a; --b;
    edges[i] = {c, {a, b}};
  }
  sort(edges.rbegin(), edges.rend());
  UnionFind uf(v);

  for(iii p : edges) {
    int a = p.second.first, b = p.second.second;
    int c = p.first;
    if(!uf.is_same_set(a, b)) {
      uf.unite(a, b);
      adj[a].push_back(edge({b, c}));
      adj[b].push_back(edge({a, c}));
    }
  }

  dfs(0);

  for(int i = 0; i < q; ++i) {
    int x;
    cin >> x;
    --x;
    cout << dist[x] << "\n";
  }
}

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 6 / 6
• Subtask 4: 10 / 10