Submission #409983

#	Time	Username	Problem	Language	Result	Execution time	Memory
409983		600Mihnea	Crocodile's Underground City (IOI11_crocodile)	C++17	89 / 100	2106 ms	144000 KiB

crocodile

#include <bits/stdc++.h>
#include "crocodile.h"

using namespace std;

typedef long long ll;

mt19937 rng((long long) (new char));
const int N = 100000 + 7;
const int INF = (int) 1e9 + 7;
int n, m, k, best[N];
multiset<int> adj[N];
vector<pair<int, int>> g[N];
queue<int> q;
bool inside[N];

void push(int i, int value) {
  if (!inside[i]) {
    q.push(i);
    inside[i] = 1;
  }
  for (auto &it : g[i]) {
    assert(adj[it.first].find(min(INF, best[i] + it.second)) != adj[it.first].end());
    adj[it.first].erase(adj[it.first].find(min(INF, best[i] + it.second)));
  }
  best[i] = value;
  for (auto &it : g[i]) {
    /**if (i == 3) {
      cout << "aici : " << best[i] << " and " << it.first << ", " << it.second << "\n";
    }**/
    adj[it.first].insert(min(INF, best[i] + it.second));
  }
}

int get_second(int a) {
  ///cout << " # " << a << "\n";
  if ((int) adj[a].size() < 2) {
    return INF;
  }
  auto it = adj[a].begin();
  it++;
  assert(it != adj[a].end());
  return *it;
}

int travel_plan(int nn, int mm, int r[][2], int len[], int kk, int ch[]) {
  n = nn;
  m = mm;
  k = kk;
 /// cout << "# " << n << " " << m << " " << k << "\n";
  for (int i = 0; i < n; i++) {
    g[i].clear();
    adj[i].clear();
    best[i] = INF;
    inside[i] = 0;
  }
  assert(q.empty());
  for (int i = 0; i < m; i++) {
   /// cout << r[i][0] << " " << r[i][1] << " and " << len[i] << "\n";
    g[r[i][0]].push_back({r[i][1], len[i]});
    g[r[i][1]].push_back({r[i][0], len[i]});
    adj[r[i][0]].insert(INF);
    adj[r[i][1]].insert(INF);
  }
  ///shuffle(ch, ch + k, rng);
  for (int i = 0; i < n; i++) {
    ///shuffle(g[i].begin(), g[i].end(), rng);
  }
  for (int i = 0; i < k; i++) {
   /// cout << i << " : " << ch[i] << "\n";
    push(ch[i], 0);
   /** if (ch[i] == 2) {
      cout << "wtf : " << i << " and " << ch[i] << "\n";
    }**/
  }
 /// cout << "kolrabi\n";
  int cnt = 0;
 /// cout << " o " << n << " " << m << " " << k << "\n";
  while (!q.empty()) {
    int a = q.front();
    inside[a] = 0;
    q.pop();
    for (auto &it : g[a]) {
      int node = it.first, relax = get_second(node);
      if (node == 2 && relax == 0) {
        ///cout << "what ? " << node << ", " << relax << "\n";
      }
      if (relax < best[node]) {
        push(node, relax);
      }
    }
  }
  /**
  cout << "print : ";
  for (auto &x : adj[2]) {
    cout << x << " ";
  }
  cout << "\n";
  exit(0);**/
 /// cout << "done\n";
  if (best[0] == INF) {
    best[0] = -1;
  }
  return best[0];
}

Compilation message (stderr)

crocodile.cpp: In function 'int travel_plan(int, int, int (*)[2], int*, int, int*)':
crocodile.cpp:77:7: warning: unused variable 'cnt' [-Wunused-variable]
   77 |   int cnt = 0;
      |       ^~~

• Subtask 1: 46 / 46
• Subtask 2: 43 / 43
• Subtask 3: 0 / 11