Submission #1252992

#	Time	Username	Problem	Language	Result	Execution time	Memory
1252992		madamadam3	World Map (IOI25_worldmap)	C++20	Compilation error	0 ms	0 KiB

worldmap

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

using namespace std;

// #define int long long int
using vi = vector<int>;
using vvi = vector<vi>;

void dfs(int u, vector<bool> &vis, vvi &adj, vi &tour) {
  vis[u] = true;
  tour.push_back(u);
  
  // sort(adj[u].begin(), adj[u].end(), [&](int a, int b) {return adj[a].size() < adj[b].size();});
  for (int v : adj[u]) {
    if (vis[v]) continue;
    dfs(v, vis, adj, tour);
    tour.push_back(u);
  }
}

vvi map_from_root(int root, int n, int m, vvi &adj, vector<set<pair<int, int>>> &diags) {
  vector<bool> vis(n+1, false); vi tour; set<int> seen;
  dfs(root, vis, adj,tour);

  int K = 3 * n - 1;
  vector<set<pair<int, int>>> diags(2*K-1);
  set<pair<int, int>> used;

  vvi ans(K, vi(K, root)), dgs(n+1);
  int cidx = 0;
  for (int i = 0; i < tour.size(); i++) {
    dgs[tour[i]].push_back(cidx+1);
    for (; cidx < 3 * i + 3; cidx++) {
      for (auto &el : diags[cidx]) {
        ans[el.first][el.second] = tour[i];
      }
    }
  }

  for (int i = 1; i <= n; i++) {
    int aidx = 0;
    for (auto &gd : dgs[i]) {
      for (auto &el : diags[gd]) {
        if (aidx >= adj[i].size()) break;
        ans[el.first][el.second] = adj[i][aidx++];
      }
    }
  }

  return ans;
}

bool is_valid(int n, int m, vvi &mp, vi a, vi b) {
  set<pair<int, int>> reqs; for (int i = 0; i < m; i++) reqs.insert({a[i], b[i]}), reqs.insert({b[i], a[i]});

  int K = mp.size();
  set<pair<int, int>> us;
  bool valid = true;
  for (int i = 0; i < K; i++) {
    for (int j = 0; j < K; j++) {
      if (!valid) break;
      
      if (i > 0) {
        valid = valid && reqs.count({mp[i-1][j], mp[i][j]});
        us.insert({mp[i-1][j], mp[i][j]});
      }
      if (j > 0) {
        valid = valid && reqs.count({mp[i][j-1], mp[i][j]});
        us.insert({mp[i][j-1], mp[i][j]});
      }
      if (i < K - 1) {
        valid = valid && reqs.count({mp[i+1][j], mp[i][j]});
        us.insert({mp[i+1][j], mp[i][j]});
      }
      if (j < K - 1) {
        valid = valid && reqs.count({mp[i][j+1], mp[i][j]});
        us.insert({mp[i][j+1], mp[i][j]});
      }
    }
  }

  return valid && us.size() == reqs.size();
}

vvi create_map(int n, int m, vi a, vi b) {
  vvi adj(n+1, vi()); for (int i = 0; i < m; i++) adj[a[i]].push_back(b[i]), adj[b[i]].push_back(a[i]);
  int K = 3 * n - 1;
  vector<set<pair<int, int>>> diags(2*K-1);
  for (int i = 0; i < K; i++) {
    for (int j = 0; j < K; j++) {
      int md = i + j;
      diags[md].insert({i, j});
    }
  }
  
  vector<int> indices(n); iota(indices.begin(), indices.end(), 1);
  sort(indices.begin(), indices.end(), [&](int a, int b) {return adj[a].size() < adj[b].size();});
  for (auto &root : indices) {
    vvi mp = map_from_root(root, n, m, adj, diags);
    if (is_valid(n, m, mp, a, b)) {
      return mp;
    }
  }

  return map_from_root(1, n, m, adj, diags);
}

Compilation message (stderr)

worldmap.cpp: In function 'vvi map_from_root(int, int, int, vvi&, std::vector<std::set<std::pair<int, int> > >&)':
worldmap.cpp:27:31: error: declaration of 'std::vector<std::set<std::pair<int, int> > > diags' shadows a parameter
   27 |   vector<set<pair<int, int>>> diags(2*K-1);
      |                               ^~~~~
worldmap.cpp:22:82: note: 'std::vector<std::set<std::pair<int, int> > >& diags' previously declared here
   22 | vvi map_from_root(int root, int n, int m, vvi &adj, vector<set<pair<int, int>>> &diags) {
      |                                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~