Submission #884221

#	Time	Username	Problem	Language	Result	Execution time	Memory
884221		vjudge1	Love Polygon (BOI18_polygon)	C++17	29 / 100	189 ms	22356 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 = 1e5 + 10, LG = 20;
vector<int> adj[N], r;
map<string, int> mp;
bitset<N> mark;
int dp[N][2];

void dfs (int v) {
  mark[v] = true;
  for (auto u: adj[v]) {
    if (!mark[u]) {
      dfs(u);
      dp[v][1] = max(dp[v][1] + max(dp[u][0], dp[u][1]), dp[v][0] + dp[u][0] + 1); 
      dp[v][0] += max(dp[u][0], dp[u][1]);
    }
  }
}

int main() {
  fast_io;
  int n = 0, m;
  cin >> m;
  for (int i = 1; i <= m; i++) {
    string s, t;
    cin >> s >> t;
    if (!mp[s]) 
      mp[s] = ++n;
    if (!mp[t]) 
      mp[t] = ++n;
    int v = mp[t], u = mp[s];
    if (v == u) {
      r.pb(u);
    }
    else {
      adj[u].pb(v);
      adj[v].pb(u);
    }
  }
  if (n & 1) kill(-1);
  int cnt = 0;
  // for (auto u: r) cout << u << ' ';
  for (auto u: r) {
    dfs(u);
    cnt += max(dp[u][0], dp[u][1]);
  }
  cout << n - cnt << '\n';
  return 0;
}

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