Submission #604839

#	Time	Username	Problem	Language	Result	Execution time	Memory
604839		Sam_a17	Stations (IOI20_stations)	C++14	0 / 100	967 ms	536 KiB

stations

#include <bits/stdc++.h>
using namespace std;
 
#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 dbg(x) cout << #x << " " << x << endl;
#define uniq(x) x.resize(unique(all(x)) - x.begin());
 
#define pb push_back
#define ld long double
#define ll long long
 
void pr(vector<int>& a) {
  cerr << "arr" << " ";
  for(auto i: a) {
    cerr << i << " "; 
  } cerr << endl;
}

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
	vector<int> labels(n), in(n);
  // vector<int> adj[n + 1];

  // for(int i = 0; i < n - 1; i++) {
  //   in[u[i]]++, in[v[i]]++;
  //   adj[u[i]].push_back(v[i]);
  //   adj[v[i]].push_back(u[i]);
  // }
 
  // int start = -1;
  // vector<int> order;
  // for(int i = 0; i < n; i++) {
  //   if(in[i] == 1) {
  //     start = i;
  //     break;
  //   }
  // }
  
  // // assert(start != -1);
  // // dfs(start, -1);

  // auto bfs = [&](int node)-> void {
  //   queue<pair<int, int>> q;
  //   q.push({node, -1});
  //   while(!q.empty()) {
  //     auto u = q.front();
  //     q.pop();

  //     order.push_back(u.first);

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

  // bfs(start);

	for (int i = 0; i < n; i++) {
		labels[i] = i;
	}
 
	return labels;
}
 
int find_next_station(int s, int t, std::vector<int> c) {
  // if(s < t) {
  //   int maxi = -1;
  //   for(auto i: c) {
  //     maxi = max(maxi, i);
  //   }
  //   return maxi;
  // } else {
  //   int mini = 10000;
  //   for(auto i: c) {
  //     mini = min(mini, i);
  //   }
  //   return mini;
  // }
 
  set<int> parentsFirst, parentsSecond;
  vector<int> toFirst(1001, -1), toSecond(1001, -1);
  int new_s = s;
  while(new_s) {
    parentsFirst.insert(new_s);
    toFirst[new_s] = new_s / 2;
    new_s /= 2;
  }

  int new_t = t, lca = -1;
  while(new_t) {
    parentsSecond.insert(new_t);
    if(parentsFirst.find(new_t) != parentsFirst.end()) {
      parentsSecond.erase(new_t);
      lca = new_t;
      break;
    }
    toSecond[new_t / 2] = new_t;
    new_t /= 2;
  }

  bool f1 = false;
  int answ = -1;
  for(auto i: c) {
    if(parentsFirst.find(i) != parentsFirst.end()) {
      f1 = true;
      if(f1) answ = min(answ, i);
      else answ = i;
    }
  }

  if(f1) {
    return answ;
  }

  bool f2 = false;
  for(auto i: c) {
    if(parentsSecond.find(i) != parentsSecond.end()) {
      f2 = true;
      if(f2) answ = max(answ, i);
      else answ = i;
    }
  }

  return answ;

	// return c[0];
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:93:18: warning: variable 'lca' set but not used [-Wunused-but-set-variable]
   93 |   int new_t = t, lca = -1;
      |                  ^~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 0 / 16
• Subtask 4: 0 / 10
• Subtask 5: 0 / 61