Submission #492062

#	Time	Username	Problem	Language	Result	Execution time	Memory
492062		lorenzoferrari	Dreaming (IOI13_dreaming)	C++14	Compilation error	0 ms	0 KiB

dreaming

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

array<int, 2> dmax;
vector<int> id, d;
vector<vector<int>> cc;
vector<vector<pair<int, int>>> g;

void comps(int v) {
  if (id[v] != -1) return;
  id[v] = cc.size() - 1;
  cc.back().push_back(v);
  for (auto [u, w] : g[v])
    comps(u);
}

void dfs(int v, int p) {
  if (d[v] > dmax[1]) dmax = {v, d[v]};
  for (auto [u, w] : g[v]) {
    if (u == p) continue;
    d[u] = d[v] + w;
    dfs(u, v);
  }
}

int diam(int v) {
  dmax = {v, 0}; dfs(v, -1);
  v = dmax[0]; d[v] = 0;
  dmax = {v, 0}; dfs(v, -1);
  return dmax[1];
}

int coda(int v) {
  // modo stupido O(n^2)
  int ans = 1e9;
  for (int u : cc[id[v]]) {
    fill(d.begin(), d.end(), 0);
    dfs(u, -1);
    ans = min(ans, *max_element(d.begin(), d.end()));
  }
  // cout << "coda[" << v << "] = " << ans << "\n";
  return ans;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
  g.resize(N);
  d.resize(N);
  id.resize(N, -1);
  for (int i = 0; i < M; ++i) {
    g[A[i]].push_back({B[i], T[i]});
    g[B[i]].push_back({A[i], T[i]});
  }
  for (int i = 0; i < N; ++i) {
    if (id[i] == -1) {
      cc.push_back(vector<int>(0));
      comps(i);
    }
  }
  int ans = 0;
  for (int i = 0; i < int(cc.size()); ++i)
    ans = max(ans, diam(cc[i][0]));
  array<int, 3> o{};
  for (int i = 0; i < int(cc.size()); ++i) {
    o[2] = max(o[2], coda(cc[i][0]));
    if (o[1] < o[2]) swap(o[1], o[2]);
    if (o[0] < o[1]) swap(o[0], o[1]);
  }
  // cout << o[0] << " " << o[1] << " " << o[2] << "\n";
  if (int(cc.size()) == 1) return ans;
  ans = max(ans, o[0] + o[1] + L);
  if (int(cc.size()) == 2) return ans;
  ans = max(ans, o[1] + o[2] + 2*L);
  return ans;
}

Compilation message (stderr)

dreaming.cpp: In function 'void comps(int)':
dreaming.cpp:14:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   14 |   for (auto [u, w] : g[v])
      |             ^
dreaming.cpp: In function 'void dfs(int, int)':
dreaming.cpp:20:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   20 |   for (auto [u, w] : g[v]) {
      |             ^
/usr/bin/ld: /tmp/ccdcMtOS.o: in function `main':
grader.c:(.text.startup+0xd1): undefined reference to `travelTime'
collect2: error: ld returned 1 exit status