제출 #1013702

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1013702		MarwenElarbi	통행료 (IOI18_highway)	C++17	90 / 100	172 ms	13588 KiB

highway

#include <bits/stdc++.h>
#include "highway.h"
using namespace std;
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ii pair<int,int>
/*
namespace {

constexpr int MAX_NUM_CALLS = 100;
constexpr long long INF = 1LL << 61;

int N, M, A, B, S, T;
std::vector<int> U, V;
std::vector<std::vector<std::pair<int, int>>> graph;

bool answered, wrong_pair;
int num_calls;

int read_int() {
  int x;
  if (scanf("%d", &x) != 1) {
    fprintf(stderr, "Error while reading input\n");
    exit(1);
  }
  return x;
}

void wrong_answer(const char *MSG) {
  printf("Wrong Answer: %s\n", MSG);
  exit(0);
}

}  // namespace

long long ask(const std::vector<int> &w) {
  if (++num_calls > MAX_NUM_CALLS) {
    wrong_answer("more than 100 calls to ask");
  }
  if (w.size() != (size_t)M) {
    wrong_answer("w is invalid");
  }
  for (size_t i = 0; i < w.size(); ++i) {
    if (!(w[i] == 0 || w[i] == 1)) {
      wrong_answer("w is invalid");
    }
  }

  std::vector<bool> visited(N, false);
  std::vector<long long> current_dist(N, INF);
  std::queue<int> qa, qb;
  qa.push(S);
  current_dist[S] = 0;
  while (!qa.empty() || !qb.empty()) {
    int v;
    if (qb.empty() ||
        (!qa.empty() && current_dist[qa.front()] <= current_dist[qb.front()])) {
      v = qa.front();
      qa.pop();
    } else {
      v = qb.front();
      qb.pop();
    }
    if (visited[v]) {
      continue;
    }
    visited[v] = true;
    long long d = current_dist[v];
    if (v == T) {
      return d;
    }
    for (auto e : graph[v]) {
      int vv = e.first;
      int ei = e.second;
      if (!visited[vv]) {
        if (w[ei] == 0) {
          if (current_dist[vv] > d + A) {
            current_dist[vv] = d + A;
            qa.push(vv);
          }
        } else {
          if (current_dist[vv] > d + B) {
            current_dist[vv] = d + B;
            qb.push(vv);
          }
        }
      }
    }
  }
  return -1;
}

void answer(int s, int t) {
  if (answered) {
    wrong_answer("answered not exactly once");
  }

  if (!((s == S && t == T) || (s == T && t == S))) {
    wrong_pair = true;
  }

  answered = true;
}*/
const int nax=130000;
vector<pair<int,int>> adj[nax];
int dis[nax];
vector<int> on(nax);
long long m,n,init;
vector<bool> vis(nax);
int bfs(int x){
  for (int i = 0; i < n; ++i)
  {
    dis[i]=1e9;
    vis[i]=0;
  }
  queue<int> q;
  q.push(x);
  dis[x]=0;
  while(!q.empty()){
    int node=q.front();
    q.pop();
    if(vis[node]) continue;
    vis[x]=true;
    for(auto u:adj[node]){
      if(dis[u.fi]<=dis[node]+1) continue;
      q.push(u.fi);
      dis[u.fi]=dis[node]+1;
    }
  }
  vector<pair<int,int>> cur;
  for (int i = 0; i < n; ++i)
  {
    cur.pb({dis[i],i});
  }
  sort(cur.begin(),cur.end(),greater<pair<int,int>>());
  int l=0;
  int r=cur.size();
  while(r-l>1){
    int mid=(r+l)/2;
    for (int i = 0; i < on.size(); ++i) on[i]=0;
    for (int i = 0; i < mid; ++i)
    {
      for(auto u:adj[cur[i].se]) on[u.se]=1;
    }
    if(ask(on)==init) l=mid;
    else r=mid;
  }
  return cur[l].se;
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
    n=N;
    m=U.size();
    vector<int> cnt;
    on.resize(U.size(),0);
    for (int i = 0; i < U.size(); ++i)
    {
      cnt.pb(0);
    }
    init=ask(cnt);
    for (int i = 0; i < U.size(); ++i)
    {
      adj[U[i]].pb({V[i],i});
      adj[V[i]].pb({U[i],i});
    }
    int S=bfs(bfs(2));
    answer(S,bfs(S));
}
/*
int main() {
  #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
  N = read_int();
  M = read_int();
  A = read_int();
  B = read_int();
  S = read_int();
  T = read_int();
  U.resize(M);
  V.resize(M);
  graph.assign(N, std::vector<std::pair<int, int>>());
  for (int i = 0; i < M; ++i) {
    U[i] = read_int();
    V[i] = read_int();
    graph[U[i]].push_back({V[i], i});
    graph[V[i]].push_back({U[i], i});
  }

  answered = false;
  wrong_pair = false;
  num_calls = 0;
  find_pair(N, U, V, A, B);
  if (!answered) {
    wrong_answer("answered not exactly once");
  }
  if (wrong_pair) {
    wrong_answer("{s, t} is wrong");
  }
  printf("Accepted: %d\n", num_calls);
  return 0;
}
*/

컴파일 시 표준 에러 (stderr) 메시지

highway.cpp: In function 'int bfs(int)':
highway.cpp:142:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  142 |     for (int i = 0; i < on.size(); ++i) on[i]=0;
      |                     ~~^~~~~~~~~~~
highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:157:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  157 |     for (int i = 0; i < U.size(); ++i)
      |                     ~~^~~~~~~~~~
highway.cpp:162:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  162 |     for (int i = 0; i < U.size(); ++i)
      |                     ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 21 / 31