제출 #737038

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
737038		AdamGS	Thousands Islands (IOI22_islands)	C++17	11.90 / 100	159 ms	21520 KiB

islands

#include "islands.h"
#include<bits/stdc++.h>
using namespace std;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const int LIM=1e5+7;
vector<int>V[LIM], S[LIM];
stack<int>Q;
int odw[LIM], kol[LIM], ile[LIM], akt;
void DFS(int x) {
  odw[x]=1;
  for(auto i : V[x]) if(!odw[i]) DFS(i);
  Q.push(x);
}
void DFS2(int x) {
  kol[x]=akt;
  for(auto i : S[x]) if(!kol[i]) DFS2(i);
}
int DFS3(int x) {
  odw[x]=1;
  if(x && ile[kol[x]]>=2) return x;
  int ok=-1;
  for(auto i : V[x]) if(!odw[i] && DFS3(i)!=-1) {
    if(!x) return i;
    ok=i;
  }
  return ok;
}
int cykl(int n) {
  rep(i, n) odw[i]=kol[i]=ile[i+1]=0;
  rep(i, n) if(!odw[i]) DFS(i);
  akt=0;
  while(!Q.empty()) {
    int p=Q.top(); Q.pop();
    if(kol[p]) continue;
    ++akt;
    DFS2(p);
  }
  rep(i, n) ++ile[kol[i]];
  rep(i, n) odw[i]=0;
  return DFS3(0);
}
variant<bool,vector<int>>find_journey(int n, int m, vector<int>X, vector<int>D) {
  multiset<pair<int,int>>A;
  rep(i, m) A.insert({X[i], D[i]});
  for(auto i : A) {
    V[i.st].pb(i.nd);
    S[i.nd].pb(i.st);
  }
  int x=cykl(n);
  if(x==-1) return false;
  A.erase(A.find({0, x}));
  rep(i, n) {
    V[i].clear();
    S[i].clear();
  }
  for(auto i : A) {
    V[i.st].pb(i.nd);
    S[i.nd].pb(i.st);
  }
  x=cykl(n);
  if(x==-1) return false;
  return true;
}

• Subtask 1: 1.75 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 0 / 21
• Subtask 4: 8.399999999999999 / 24
• Subtask 5: 0 / 45