oj.uz

답안 #292675

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
292675 2020-09-07T11:41:01 Z Haunted_Cpp Simurgh (IOI17_simurgh) C++17
0 / 100
 1 ms 384 KB 
#include "simurgh.h"
#include <bits/stdc++.h>
using namespace std;

vector<int> par, s;

void reset(int n) {
  for (int i = 0; i < n; i++) {
    par[i] = i;
    s[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 (s[a] < s[b]) swap(a, b);
  par[b] = a;
  s[a] += s[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;
  par = s = vector<int>(n);
  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;
  }
  vector<int> best_way;
  for (auto &edge : span) {
    int starting_edge = edge;
    bool swap = false;
    const int st = u[edge];
    const int et = v[edge];
    best_way.clear();
    for (auto [nxt, w] : g[st]) {
      best_way.emplace_back(w);
    }
    for (auto [nxt, w] : g[et]) {
      best_way.emplace_back(w);
    }
    for (auto to : best_way) {
      reset(n);
      edge = to;
      if(!works(span, u, v)) {
        continue;
      }
      int nxt_score = count_common_roads(span);
      if (nxt_score > score) {
        score = nxt_score;
        assert(edge == to);
        swap = true;
        break;
      }
    }
    if (!swap) {
      edge = starting_edge;
    }
  }
  return span;
}

Subtask #1
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB correct
2 Incorrect 0 ms 384 KB WA in grader: NO
3 Halted 0 ms 0 KB -

Subtask #2
0 / 17.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB correct
2 Incorrect 0 ms 384 KB WA in grader: NO
3 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB correct
2 Incorrect 0 ms 384 KB WA in grader: NO
3 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB correct
2 Incorrect 1 ms 288 KB WA in grader: NO
3 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 384 KB correct
2 Incorrect 0 ms 384 KB WA in grader: NO
3 Halted 0 ms 0 KB -