제출 #578036

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
578036		Sam_a17	관광지 (IZhO14_shymbulak)	C++14	0 / 100	1593 ms	17492 KiB

shymbulak

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;

#pragma GCC optimize("Ofast")

#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif

#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());

#define pb push_back
#define popf pop_front
#define popb pop_back

void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}

template <class T> void print(set <T> v);
template <class T> void print(vector <T> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T, class V> void print(pair <T, V> p);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(unordered_map<T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'

// for grid problems
long long dx[8] = {-1,0,1,0,1,-1,1,-1};
long long dy[8] = {0,1,0,-1,1,1,-1,-1};

// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();

  if (str != "" && str != "input") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }

  if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  }
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const long long N = 2e5 + 10;
vector<long long> adj[N], cycle;
long long n, p[N], maxDist, depth[N];
pair<long long, long long> answNode[N];
bool used[N];
long long answ;


bool flag = false;
void getCycle(long long node, long long parent) {
  used[node] = true;
  p[node] = parent;
  for(auto i: adj[node]) {
    if(i == parent) continue;
    if(used[i]) {
      // we get cycle
      long long curr = node;
      while(curr != i) {
        // dbg(curr)
        cycle.push_back(curr);
        curr = p[curr];
      } cycle.push_back(i); 
      flag = true;
      // dbg(cycle)
      return;
    } else {
      getCycle(i, node);
    }

    if(flag) {
      return;
    }
  }
}

pair<long long, long long> getFurthest(long long node) {
  memset(used, false, sizeof(used));
  queue<pair<long long, long long>> q;
  q.push({node, 0});
  used[node] = true;

  pair<long long, long long> answ = {node, 0};
  while(!q.empty()) {
    auto u = q.front();
    q.pop();

    for(auto i: adj[u.first]) {
      if(used[i]) continue;
      used[i] = true;
      q.push({i, u.second + 1});

      if(u.second + 1 > answ.second) {
        answ = {i, u.second + 1};
      }
    }
  }
  
  return answ;
}

// dp
pair<long long, long long> dfs(long long node, long long parent) {
  vector<pair<long long, long long>> answers;
  
  for(auto i: adj[node]) {
    if(used[i] || i == parent) continue;

    depth[i] = depth[node] + 1;
    answers.push_back(dfs(i, node));
  }

  if(sz(answers) >= 2) {
    sort(all(answers));
    long long size = sz(answers);

    if(answers[size - 1].first == answers[size - 2].first) {
      long long dist = 2 * (answers[size - 1].first - depth[node]);
      long long ansi = 0, all = 0;

      size--;
      // dbg(answers)
      while(size >= 0 && answers[size].first == answers.back().first) {
        ansi += all * answers[size].second;
        all += answers[size--].second;
      }

      answers[sz(answers) - 1].second = all;

      if(dist != maxDist) {
        answNode[node] = {answers.back()};
        return {answers.back()};
      }

      answ += ansi;
    } else {
      long long dist = answers[size - 1].first + answers[size - 2].first - 2 * depth[node];
      if(dist != maxDist) {
        answNode[node] = {answers.back()};
        return {answers.back()};
      }
      
      long long l = answers.back().second, r = 0, it = size - 2;

      size -= 2;
      while(size >= 0 && answers[size].first == answers[it].first) {
        r += answers[size--].second;
      }

      answ += l * r;
    }
  }

  if(answers.empty()) {
    answNode[node] = {depth[node], 1};
    return {depth[node], 1};
  } else {
    answNode[node] = {answers.back()};
    return {answers.back()};
  }
}

void solve_() {
  cin >> n;
  for(int i = 1; i <= n; i++) {
    long long a, b; cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }

  // we get the path which contain cycle  
  getCycle(1, 0);

  // we should calc the max distance
  maxDist = getFurthest(getFurthest(1).first).second;

  dbg(cycle)

  // get cycle used 
  memset(used, false, sizeof(used));
  for(auto i: cycle) {
    used[i] = true;
  }

  for(auto i: cycle) {
    dfs(i, 0);
  }

  dbg(answ)
  for(int i = 0; i < sz(cycle); i++) {
    for(int j = i + 1; j < sz(cycle); j++) {
      long long minDist = min((long long)(j - i), (long long)(i + sz(cycle) - j));

      long long A = cycle[i], B = cycle[j];

      if(answNode[A].first + answNode[B].first + minDist == maxDist) {
        if(sz(cycle) % 2 == 0 && minDist == sz(cycle) / 2) {
          answ += 2 * (answNode[A].second * answNode[B].second);
        } else {
          answ += (answNode[A].second * answNode[B].second);
        }
      }
    }
  }
  

  printf("%lld\n", answ);
}

int main() {
  setIO();

  auto solve = [&](int test_case)-> void {
    while(test_case--) {
      solve_();
    }
  };

  int test_cases = 1;
  solve(test_cases);

  return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

shymbulak.cpp: In function 'void setIO(std::string)':
shymbulak.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
shymbulak.cpp:66:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
shymbulak.cpp:70:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
shymbulak.cpp:71:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 20
• Subtask 3: 0 / 50