Submission #880883

#	Time	Username	Problem	Language	Result	Execution time	Memory
880883		vjudge1	Love Polygon (BOI18_polygon)	C++17	0 / 100	63 ms	19864 KiB

polygon

#include <bits/stdc++.h>
#define file_io freopen("input.txt", "r", stdin);freopen("output.txt", "w", stdout);
#define fast_io ios::sync_with_stdio(false);cin.tie(0);
#define what(x) cerr << #x << " is " << x << '\n';
#define kill(x) {cout << x << '\n'; return 0;}
#define all(x) (x).begin(), (x).end()
#define pii pair<int, int>
#define pb push_back
#define ll long long
#define F first
#define S second
const ll inf = 1e18, mod = 1e9 + 7, delta = 1e9 + 9, SQ = 450, P = 6065621;

using namespace std;

const ll N = 2e5 + 10, LG = 31;
int go[N], cnt[N], c, ans, bad, b[N], par[N];
unordered_map<string, int> tmpMadarJende;
bool mark[N], in[N], state[N];
vector<int> back[N];

void dfs (int v, int p = -1) {
  par[v] = p;
  if (!back[v].size() && !state[p]) {
    ++ans;
    // what(p);
    // what(v);
    b[par[p]]++;
    b[p]++;
    state[p] = true;
    state[v] = true;
    return;
  }
  for (auto u: back[v]) {
    if (u - p) dfs(u, v);
  }
  if (state[p] && b[v] == back[v].size()) {
    ++bad;
    return;
  }
}

int main() {
  fast_io;
  int m, n = 0;
  cin >> m;
  while (m--) {
    string s, t;
    cin >> s >> t;
    if (!tmpMadarJende[s]) tmpMadarJende[s] = ++n;
    if (!tmpMadarJende[t]) tmpMadarJende[t] = ++n;
    if (s == t) in[tmpMadarJende[s]] = true;
    else {
      cnt[tmpMadarJende[t]]++;
      go[tmpMadarJende[s]] = tmpMadarJende[t];
      back[tmpMadarJende[t]].pb(tmpMadarJende[s]);
    }
  }
  if (n & 1) kill(-1);
  for (int i = 1; i <= n; i++) {
    if (in[i] && !cnt[i]) {
      ++bad;
      continue;
    }
    if (in[i]) dfs(i);
  }
  cout << bad + ans << '\n';
  // what(bad);
  // what(ans);
  return 0;
}

Compilation message (stderr)

polygon.cpp: In function 'void dfs(int, int)':
polygon.cpp:37:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |   if (state[p] && b[v] == back[v].size()) {
      |                   ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 21
• Subtask 2: 0 / 25
• Subtask 3: 0 / 29
• Subtask 4: 0 / 25