oj.uz

Submission #74212

# Submission time Handle Problem Language Result Execution time Memory
74212 2018-08-30T13:34:24 Z funcsr Towns (IOI15_towns) C++17
48 / 100
 43 ms 720 KB 
#include "towns.h"
#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <cassert>
#include <random>
#define rep(i, N) for (int i=0; i<(N); i++)
#define pb push_back
#define _1 first
#define _2 second
#define all(x) x.begin(), x.end()
#define uniq(x) x.erase(unique(all(x)), x.end())
#define INF 1145141919
using namespace std;
typedef pair<int, int> P;
struct UF {
  int U[111];
  int R[111];
  UF(int N) {
    rep(i, N) U[i] = i, R[i] = 1;
  }
  int find(int x) {
    if (U[x]==x)return x;
    return U[x]=find(U[x]);
  }
  void unite(int x, int y) {
    x=find(x), y=find(y);
    if(x==y)return;
    U[y]=x;
    R[x]+=R[y];
    R[y]=0;
  }
};
mt19937 mt_rand(12345);

int N;
int memo[111][111];
int Rank[111];
int Q = 0;
int dist(int a, int b) {
  if (memo[a][b] != -1) return memo[a][b];
  if (a == b) return 0;
  Q++;
  return memo[a][b] = memo[b][a] = getDistance(a, b);
}
int saien(int x) {
  P mp = P(-1, -1);
  rep(t, N) mp = max(mp, P(dist(x, t), t));
  return mp._2;
}
bool same(int x, int y) {
  if (x==y)return true;
  return dist(x,y)-Rank[x]-Rank[y]!=0;
}

int hubDistance(int NN, int sub) {
  N=NN;
  rep(i, N) rep(j, N) memo[i][j] = -1;
  rep(i, N) Rank[i] = -1;

  int u = saien(0);
  int v = saien(u);
  vector<int> pos;
  int L = dist(u, v);
  pos.pb(0);
  pos.pb(L);
  map<int, vector<int> > G;
  rep(x, N) if (x != u && x != v) {
    Rank[x] = (dist(u, x)+dist(v, x)-L)/2;
    int p = dist(u, x)-Rank[x];
    //cout<<"x="<<x<<"->"<<p<<"\n";
    pos.pb(p);
    G[p].pb(x);
  }
  sort(all(pos)); uniq(pos);
  //for (int x : pos)cout<<x<<",";cout<<"\n";
  int R = INF;
  for (int x : pos) R = min(R, max(x, L-x));
  vector<int> gs;
  for (int x : pos) if (R == max(x, L-x)) gs.pb(x);
  assert(gs.size()==1||gs.size()==2);

  bool ok = false;
  for (int g : gs) {
    vector<int> list = G[g];
    int left = 1;
    for (int x : pos) if (x<g) left += G[x].size();
    int right = 1;
    for (int x : pos) if (x>g) right += G[x].size();
    int maxsize = max(left, right);
    assert(left+right+list.size()==N);
    if (maxsize <= N/2 && list.size() > N/2) {
      if (sub == 4) {
        maxsize = max(maxsize, (int)list.size());
      }
      else if (sub >= 3) {
        int Qlimit = INF;
        if (sub == 5) Qlimit = 5*N;
        else if (sub == 6) Qlimit = (7*N+1)/2;
        UF uf(N);
        rep(_, 4) {
          int x = list[mt_rand()%list.size()];
          int ctr = 0;
          for (int y : list) {
            if (uf.find(x) == uf.find(y)) {
              ctr++;
              continue;
            }
            if (Q<Qlimit && same(x, y)) {
              ctr++;
              uf.unite(x, y);
            }
            if (ctr > N/2) break;
          }
          maxsize = max(maxsize, ctr);
          if (maxsize > N/2) break;
        }
      }
    }
    //cout<<"R="<<R<<", size="<<maxsize<<"\n";
    if (maxsize <= N/2) {
      ok = true;
      break;
    }
  }
  if (!ok) R *= -1;
  return R;
}

Compilation message

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:88:50: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
     for (int x : pos) if (x<g) left += G[x].size();
                                                  ^
towns.cpp:90:51: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
     for (int x : pos) if (x>g) right += G[x].size();
                                                   ^
In file included from /usr/include/c++/7/cassert:44:0,
                 from towns.cpp:6:
towns.cpp:92:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     assert(left+right+list.size()==N);
            ~~~~~~~~~~~~~~~~~~~~~~^~~
towns.cpp:93:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (maxsize <= N/2 && list.size() > N/2) {
                           ~~~~~~~~~~~~^~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 376 KB Output is correct
2 Correct 16 ms 512 KB Output is correct
3 Correct 2 ms 512 KB Output is correct
4 Correct 24 ms 552 KB Output is correct
5 Correct 21 ms 552 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 628 KB Output is correct
2 Correct 16 ms 672 KB Output is correct
3 Correct 23 ms 680 KB Output is correct
4 Correct 43 ms 680 KB Output is correct

Subtask #3
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 680 KB Output is correct
2 Correct 23 ms 720 KB Output is correct
3 Correct 2 ms 720 KB Output is correct
4 Correct 24 ms 720 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 720 KB Output is correct

Subtask #5
0 / 13.0

# Verdict Execution time Memory Grader output
1 Incorrect 18 ms 720 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 39.0

# Verdict Execution time Memory Grader output
1 Incorrect 21 ms 720 KB Output isn't correct
2 Halted 0 ms 0 KB -