oj.uz

Submission #632094

# Submission time Handle Problem Language Result Execution time Memory
632094 2022-08-19T12:24:37 Z TimDee Thousands Islands (IOI22_islands) C++17
55 / 100
 40 ms 12844 KB 
#include "islands.h"
#include <bits/stdc++.h>
using namespace std;

int n,m;
vector<int> u,v;

vector<int> vis(1e5+3,0);
vector<int> par(1e5+3,-1);
vector<vector<int>> adj(1e5+3,vector<int>(0));

int cycpt=-1;
vector<int> cyc;
int color=2;

void dfs(int u) {

  if (vis[u]==color) {cyc.push_back(u); cycpt=u; return;}
  else if (vis[u]) return;
  vis[u]=2;

  for (auto v:adj[u]) {

    dfs(v);
    if (cycpt!=-1) {
      cyc.push_back(u);
      return;
    }

  }
  vis[u]=1;

}

//#define false {}
//#define true {}
variant<bool, std::vector<int>>
//vector<int>
find_journey(int N, int M, vector<int> U, vector<int> V) {

  n=N,m=M,u=U,v=V;
  if (n==2) {
    vector<int> fv,sv;
    for (int x=0; x<m; ++x) if (u[x]==0) fv.push_back(x); else sv.push_back(x);
      int f=fv.size(), s=sv.size();
    if (f>=2 && s) {
      vector<int> r={fv[0],sv[0],fv[1],fv[0],sv[0],fv[1]};;
      return r;
    } 
    else return false;
  }

  vector<vector<int>>__p2(n,vector<int>(n,0));
  int _p2=1;
  for (int i=0; i<m; ++i) {
    __p2[u[i]][v[i]]=1;
  }
  for (int i=0; i<n; ++i) {
    for (int j=0; j<n; ++j) {
      if (i==j) continue;
      _p2&=__p2[i][j];
    }
  }

  if (_p2) {

    int a,b,c,d; 
    for (int i=0; i<m; ++i) {
      if (u[i]==0 && v[i]==1) a=i;
      if (u[i]==0 && v[i]==2) b=i;
      if (u[i]==1 && v[i]==0) c=i;
      if (u[i]==2 && v[i]==0) d=i;
    }
    vector<int> r = {a,c,b,d,c,a,d,b};
    return r;

  }

  int _p3=1, _p4=1;
  for (int i=0; i<m; i+=2) {
    _p3&=((u[i]==v[i+1])&&(v[i]==u[i+1]));
    _p4&=((u[i]==u[i+1])&&(v[i]==v[i+1]));
  }

  if (_p3) {

    vector<int> deg(1e5+3,0);
    for (int i=0; i<m; i+=2) {
      deg[u[i]]++;
      deg[v[i]]++;
      adj[u[i]].push_back(v[i]);
      adj[v[i]].push_back(u[i]);
    }

    int mx=0;
    for (auto x:deg) mx=max(mx,x);

    if (deg[0]>=2) {
      int a=-1,b=-1,c=-1,d=-1;
      int f=-1,s=-1;
      for (auto x:adj[0]) {
        if (f==-1) f=x;
        else {s=x; break;}
      }
      for (int i=0; i<m; ++i) {
        if (u[i]==0 && v[i]==f) a=i;
        if (u[i]==0 && v[i]==s) b=i;
        if (u[i]==f && v[i]==0) c=i;
        if (u[i]==s && v[i]==0) d=i;
      }
      vector<int> r = {a,c,b,d,c,a,d,b};
      return r;
    }
    if (mx<3) return false;

    vis[0]=1;
    queue<int> q; q.push(0);
    while (!q.empty()) {
      int x=q.front(); q.pop();
      if (deg[x]>=3) {

        vector<int> r;
        int a=-1,b=-1,c=-1,d=-1;
        vector<int> path;
        int p=x;
        while (p!=0) {
          for (int i=0; i<m; ++i) {
            if (u[i]==par[p] && v[i]==p) {
              path.push_back(i);
              break;
            }
          }
          p=par[p];
        }
        for (int i=path.size()-1; i>=0; --i) r.push_back(path[i]);

        int f=-1, s=-1;
        for (auto y:adj[x]) {
          if (y==par[x]) continue;
          if (f==-1) f=y;
          else {s=y; break;}
        }

        //cout<<f<<' '<<s<<'\n';
        if (f!=s) for (int i=0; i<m; ++i) {
          if (u[i]==x && v[i]==f) a=i;
          if (u[i]==x && v[i]==s) b=i;
          if (u[i]==f && v[i]==x) c=i;
          if (u[i]==s && v[i]==x) d=i;
        } else for (int i=0; i<m; ++i) {
          if (u[i]==x && v[i]==f && a==-1) a=i;
          if (u[i]==x && v[i]==s && a!=-1) b=i;
          if (u[i]==f && v[i]==x && c==-1) c=i;
          if (u[i]==s && v[i]==x && c!=-1) d=i;
        }
        vector<int> paiu={a,c,b,d,c,a,d,b};
        for (auto x:paiu) r.push_back(x);
        for (int i=0; i<path.size(); ++i) r.push_back(path[i]);
        return r;

      }
      for (auto y:adj[x]) {
        if (!vis[y]) {
          q.push(y);
          vis[y]=1;
          par[y]=x;
        }
      }
    }

    return false;

  }

  if (_p4) {

    for (int i=0; i<m; i+=2) {
      adj[u[i]].push_back(v[i]);
    }

    dfs(0); //cout<<cycpt;

    if (cycpt==-1) return false;
    
    vector<int> r;
    vector<int> path;
    //for (auto x:cyc) cout<<x<<' '; cout<<'\n';
    for (int i=cyc.size()-1; i; --i) {
      for (int j=0; j<m; ++j) {
        if (v[j]==cyc[i-1] && u[j]==cyc[i]) { path.push_back(j); break; }
      }
    }
    int save=-1;
    for (auto x:path) r.push_back(x);
    for (int i=cyc.size()-1; i; --i) {
      if (cyc[i]!=cycpt) continue;
      for (int j=0; j<m; ++j) {
        if (v[j]==cyc[i-1] && u[j]==cyc[i]) { save=j; r.push_back(j+1); r.push_back(j); break; }
      }
      break;
    }
    reverse(path.begin(),path.end());
    for (auto x:path) {if (x!=save) r.push_back(x); else r.push_back(x+1); }

    return r;

  }

}

Compilation message

islands.cpp: In function 'std::variant<bool, std::vector<int, std::allocator<int> > > find_journey(int, int, std::vector<int>, std::vector<int>)':
islands.cpp:158:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  158 |         for (int i=0; i<path.size(); ++i) r.push_back(path[i]);
      |                       ~^~~~~~~~~~~~
islands.cpp:53:45: warning: control reaches end of non-void function [-Wreturn-type]
   53 |   vector<vector<int>>__p2(n,vector<int>(n,0));
      |                                             ^
islands.cpp:74:37: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
   74 |     vector<int> r = {a,c,b,d,c,a,d,b};
      |                                     ^
islands.cpp:74:37: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:74:37: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:74:37: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 2 ms 3412 KB Output is correct
3 Correct 2 ms 3412 KB Output is correct
4 Correct 2 ms 3412 KB Output is correct
5 Correct 2 ms 3412 KB Output is correct
6 Correct 2 ms 3412 KB Output is correct
7 Correct 34 ms 9120 KB Output is correct

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 2 ms 3412 KB Output is correct
3 Correct 2 ms 3412 KB Output is correct
4 Correct 2 ms 3420 KB Output is correct
5 Correct 2 ms 3412 KB Output is correct
6 Correct 27 ms 7752 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 7892 KB Output is correct
2 Correct 2 ms 3796 KB Output is correct
3 Correct 2 ms 3412 KB Output is correct
4 Correct 2 ms 3796 KB Output is correct
5 Correct 4 ms 7764 KB Output is correct
6 Correct 2 ms 3796 KB Output is correct
7 Correct 4 ms 7764 KB Output is correct
8 Correct 2 ms 3796 KB Output is correct
9 Correct 2 ms 3796 KB Output is correct
10 Correct 6 ms 7764 KB Output is correct
11 Correct 2 ms 3412 KB Output is correct
12 Correct 6 ms 7868 KB Output is correct
13 Correct 2 ms 3796 KB Output is correct
14 Correct 2 ms 3796 KB Output is correct
15 Correct 2 ms 3796 KB Output is correct
16 Correct 2 ms 3796 KB Output is correct
17 Correct 22 ms 10628 KB Output is correct
18 Correct 22 ms 10220 KB Output is correct
19 Correct 2 ms 3412 KB Output is correct
20 Correct 2 ms 3412 KB Output is correct
21 Correct 2 ms 3412 KB Output is correct
22 Correct 2 ms 3412 KB Output is correct
23 Correct 28 ms 7764 KB Output is correct

Subtask #4
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 3 ms 3540 KB Output is correct
3 Correct 29 ms 8148 KB Output is correct
4 Correct 37 ms 12148 KB Output is correct
5 Correct 5 ms 6740 KB Output is correct
6 Correct 4 ms 6740 KB Output is correct
7 Correct 2 ms 3412 KB Output is correct
8 Correct 2 ms 3412 KB Output is correct
9 Correct 2 ms 3412 KB Output is correct
10 Correct 5 ms 7508 KB Output is correct
11 Correct 5 ms 7508 KB Output is correct
12 Correct 5 ms 7508 KB Output is correct
13 Correct 6 ms 7584 KB Output is correct
14 Correct 5 ms 7508 KB Output is correct
15 Correct 5 ms 7508 KB Output is correct
16 Correct 5 ms 7380 KB Output is correct
17 Correct 2 ms 3412 KB Output is correct
18 Correct 5 ms 7508 KB Output is correct
19 Correct 4 ms 7380 KB Output is correct
20 Correct 34 ms 8716 KB Output is correct
21 Correct 33 ms 12244 KB Output is correct
22 Correct 4 ms 7508 KB Output is correct
23 Correct 5 ms 7424 KB Output is correct
24 Correct 2 ms 3412 KB Output is correct
25 Correct 2 ms 3412 KB Output is correct
26 Correct 5 ms 7536 KB Output is correct
27 Correct 35 ms 12500 KB Output is correct
28 Correct 35 ms 12540 KB Output is correct
29 Correct 3 ms 3540 KB Output is correct
30 Correct 39 ms 12844 KB Output is correct
31 Correct 2 ms 3412 KB Output is correct
32 Correct 36 ms 12336 KB Output is correct
33 Correct 30 ms 8516 KB Output is correct
34 Correct 20 ms 9988 KB Output is correct
35 Correct 3 ms 4692 KB Output is correct
36 Correct 31 ms 11600 KB Output is correct
37 Correct 40 ms 12468 KB Output is correct
38 Correct 3 ms 4436 KB Output is correct
39 Correct 32 ms 8616 KB Output is correct
40 Correct 5 ms 7380 KB Output is correct
41 Correct 37 ms 12732 KB Output is correct
42 Correct 36 ms 12492 KB Output is correct
43 Correct 2 ms 3412 KB Output is correct
44 Correct 4 ms 7508 KB Output is correct
45 Correct 5 ms 7508 KB Output is correct
46 Correct 19 ms 9580 KB Output is correct

Subtask #5
0.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 2 ms 3412 KB Output is correct
3 Correct 2 ms 3412 KB Output is correct
4 Correct 2 ms 3412 KB Output is correct
5 Correct 2 ms 3412 KB Output is correct
6 Correct 2 ms 3412 KB Output is correct
7 Correct 34 ms 9120 KB Output is correct
8 Correct 2 ms 3412 KB Output is correct
9 Correct 2 ms 3412 KB Output is correct
10 Correct 2 ms 3412 KB Output is correct
11 Correct 2 ms 3420 KB Output is correct
12 Correct 2 ms 3412 KB Output is correct
13 Correct 27 ms 7752 KB Output is correct
14 Correct 6 ms 7892 KB Output is correct
15 Correct 2 ms 3796 KB Output is correct
16 Correct 2 ms 3412 KB Output is correct
17 Correct 2 ms 3796 KB Output is correct
18 Correct 4 ms 7764 KB Output is correct
19 Correct 2 ms 3796 KB Output is correct
20 Correct 4 ms 7764 KB Output is correct
21 Correct 2 ms 3796 KB Output is correct
22 Correct 2 ms 3796 KB Output is correct
23 Correct 6 ms 7764 KB Output is correct
24 Correct 2 ms 3412 KB Output is correct
25 Correct 6 ms 7868 KB Output is correct
26 Correct 2 ms 3796 KB Output is correct
27 Correct 2 ms 3796 KB Output is correct
28 Correct 2 ms 3796 KB Output is correct
29 Correct 2 ms 3796 KB Output is correct
30 Correct 22 ms 10628 KB Output is correct
31 Correct 22 ms 10220 KB Output is correct
32 Correct 2 ms 3412 KB Output is correct
33 Correct 2 ms 3412 KB Output is correct
34 Correct 2 ms 3412 KB Output is correct
35 Correct 2 ms 3412 KB Output is correct
36 Correct 28 ms 7764 KB Output is correct
37 Runtime error 4 ms 6740 KB Execution killed with signal 11
38 Halted 0 ms 0 KB -