제출 #292670

#제출 시각아이디문제언어결과실행 시간메모리
292670Haunted_CppSimurgh (IOI17_simurgh)C++17
30 / 100
3052 ms3576 KiB
#include "simurgh.h"
#include <bits/stdc++.h>
using namespace std;

struct DisjointSet {
  vector<int> par, size;
  DisjointSet(int n) {
    par = size = vector<int>(n);
    for (int i = 0; i < n; i++) {
      par[i] = i;
      size[i] = 1;
    }
  }
  int root(int x) {
    if (x == par[x]) return x;
    return par[x] = root(par[x]);
  }
  void join(int a, int b) {
    a = root(a);
    b = root(b);
    if (a == b) return;
    if (size[a] < size[b]) swap(a, b);
    par[b] = a;
    size[a] += size[b];
  }
  bool is(int a, int b) {
    return root(a) == root(b);
  }
  bool works(const vector<int> &span, const vector<int> &u, const vector<int> &v) {
    for (auto to : span) {
      const int st = u[to];
      const int et = v[to];
      if (is(st, et)) return false;
      join(st, et);
    }
    return true;
  }
};

const int MAX_N = 240 + 5;

vector<vector<pair<int, int>>> g(MAX_N);
bitset<MAX_N> vis;

vector<int> span;

void get_any(int node) {
  vis[node] = 1;
  for (auto [nxt, to] : g[node]) {
    if (!vis[nxt]) {
      vis[nxt] = 1;
      span.emplace_back(to);
      get_any(nxt);
    }
  }  
}

vector<int> find_roads(int n, vector<int> u, vector<int> v) {
  const int m = v.size();
  const int t = n - 1;
  for (int i = 0; i < m; i++) {
    const int st = u[i];
    const int et = v[i];
    g[st].emplace_back(et, i);
    g[et].emplace_back(st, i);
  }
  get_any(0);
  int score = count_common_roads(span);
  if (score == t) {
    return span;
  }
  for (auto &edge : span) {
    int starting_edge = edge;
    bool swap = false;
    for (int i = 0; i < m; i++) {
      DisjointSet DSU(n);
      edge = i;
      if(!DSU.works(span, u, v)) {
        continue;
      }
      int nxt_score = count_common_roads(span);
      if (nxt_score > score) {
        score = nxt_score;
        assert(edge == i);
        swap = true;
        break;
      }
    }
    if (!swap) {
      edge = starting_edge;
    }
  }
  return span;
}
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...