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Submission #862882

# Submission time Handle Problem Language Result Execution time Memory
862882 2023-10-19T08:19:23 Z iskhakkutbilim Love Polygon (BOI18_polygon) C++17
75 / 100
 259 ms 47056 KB 
#include <bits/stdc++.h>
using namespace std;

#define int long long
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int N = 1e5;

int n;
vector<string> a, b;
vector<string> compr;
map<string,int> compress;



vector<int> g[N+10];
int used[N + 10];
vector<int> G[N+10];
int idx[N+10];
vector<int> topo;
int num=1;

vector<int> sub[N+10];

void dfs(int v){
	used[v] = 1;
	for(int to : g[v]){
		if(!used[to]){
			dfs(to);
		}
	}
	topo.push_back(v);
}

void dfs2(int v){
	used[v] = 1;
	idx[v] = num;
	sub[num].push_back(v);
	for(int to : G[v]){
		if(!used[to]){
			dfs2(to);
		}
	}
}
int ans;
vector<int> cond[N+10];
int taken[N + 10];
void dfs3(int v, int par){
	used[v] = 1;
	for(int to : cond[v]){
		if(used[to]) continue;
		dfs3(to, v);
	}
	if(par != -1 && !taken[par] && !taken[v]){
//		cout << v << " " << par << '\n';
		taken[v] = taken[par] = 1;
		ans++;
	}
}


main(){
   ios::sync_with_stdio(0);
   cin.tie(0); cout.tie(0);
	cin >> n;
	a.resize(n);
	b.resize(n);
	for(int i = 0;i < n; i++){
		cin >> a[i] >> b[i];
		compr.push_back(a[i]);
	}
	sort(all(compr));
	int cnt1 = 1;
	for(auto x : compr){
		compress[x] = cnt1++;
	}
//	for(int i = 0;i < n; i++){
//		cout << a[i] << " = " << compress[a[i]] << '\n';
//	}
	for(int i = 0;i < n; i++){
		g[compress[a[i]]].push_back(compress[b[i]]);
		G[compress[b[i]]].push_back(compress[a[i]]);
	}
	if(n%2 == 1){
		cout << "-1";
		return 0;
	}
//	if(n <= 20){
//		vector<int> dp((1<<n), INT_MAX);
//		dp[0] = 0;
//		for(int mask = 0; mask < (1<<n); mask++){
//			for(int i = 0;i < n; i++){
//				for(int j = i + 1; j < n; j++){
//					int new_mask = mask | (1<<i);
//					new_mask|= (1<<j);
//					int c = (g[i+1][0] != j + 1) + (g[j + 1][0] != (i + 1));
//					dp[new_mask] = min(dp[new_mask], dp[mask] + c);
//				}
//			}
//		}
//		cout << dp[(1<<n)-1];
//		return 0;
//	}
	
	
	for(int i = 1;i <= n; i++){
		if(!used[i]){
			dfs(i);
		}
	}
	reverse(all(topo));
	for(int i = 1;i <= n; i++) used[i] = 0;
	for(int i : topo){
		if(!used[i]){
			dfs2(i);
			num++;
		}
	}
	for(int i = 1;i <= n; i++){
		int cnt = sub[i].size();
		if(cnt > 2){
			ans+= (cnt / 2);
		}
		if(cnt % 2 == 0){
			taken[i] = 1;
		}
	}
	
	for(int i = 1;i <= n; i++){
		set<int> st;
		for(int to : g[i]){
			if(idx[i] != idx[to]){
				st.insert(idx[to]);
			}
		}
		for(int u : st){
			cond[idx[i]].push_back(u);
			cond[u].push_back(idx[i]);
		}
	}
//	for(int i = 1;i < num; i++){
//		cout << i << " = ";
//		for(int x : sub[i]){
//			cout << x << ' ';
//		}
//		cout << '\n';
//	}
	for(int i = 1;i <= n; i++){
		used[i] = 0;
	}
	
	for(int i = 1;i < num; i++){
		if(!used[i]){
			dfs3(i, -1);
		}
	}
	for(int i = 1;i < num; i++){
		if(taken[i] != 1) ans++;
	}
	
	
	cout << ans;
	return 0;
}

Compilation message

polygon.cpp:63:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   63 | main(){
      | ^~~~

Subtask #1
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 11868 KB Output is correct
2 Correct 2 ms 11868 KB Output is correct
3 Correct 2 ms 11868 KB Output is correct
4 Correct 3 ms 11868 KB Output is correct
5 Correct 3 ms 11864 KB Output is correct
6 Correct 2 ms 11864 KB Output is correct
7 Correct 2 ms 12000 KB Output is correct
8 Correct 3 ms 11868 KB Output is correct
9 Correct 2 ms 11868 KB Output is correct
10 Correct 3 ms 11868 KB Output is correct
11 Correct 2 ms 11864 KB Output is correct
12 Correct 3 ms 11868 KB Output is correct
13 Correct 2 ms 11868 KB Output is correct
14 Correct 2 ms 11868 KB Output is correct
15 Correct 3 ms 11868 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 11868 KB Output is correct
2 Correct 3 ms 11868 KB Output is correct
3 Correct 2 ms 11868 KB Output is correct
4 Correct 205 ms 43344 KB Output is correct
5 Correct 202 ms 37812 KB Output is correct
6 Correct 215 ms 42928 KB Output is correct
7 Correct 188 ms 36036 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 231 ms 42172 KB Output is correct
2 Correct 251 ms 43332 KB Output is correct
3 Correct 173 ms 39876 KB Output is correct
4 Correct 185 ms 34016 KB Output is correct
5 Correct 259 ms 47056 KB Output is correct
6 Correct 216 ms 41920 KB Output is correct
7 Correct 217 ms 41920 KB Output is correct
8 Correct 199 ms 40764 KB Output is correct
9 Correct 218 ms 41664 KB Output is correct
10 Correct 152 ms 40952 KB Output is correct
11 Correct 2 ms 11868 KB Output is correct
12 Correct 2 ms 11868 KB Output is correct
13 Correct 2 ms 12000 KB Output is correct
14 Correct 2 ms 11868 KB Output is correct

Subtask #4
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 11868 KB Output is correct
2 Correct 2 ms 11868 KB Output is correct
3 Correct 2 ms 11868 KB Output is correct
4 Correct 3 ms 11868 KB Output is correct
5 Correct 3 ms 11864 KB Output is correct
6 Correct 2 ms 11864 KB Output is correct
7 Correct 2 ms 12000 KB Output is correct
8 Correct 3 ms 11868 KB Output is correct
9 Correct 2 ms 11868 KB Output is correct
10 Correct 3 ms 11868 KB Output is correct
11 Correct 2 ms 11864 KB Output is correct
12 Correct 3 ms 11868 KB Output is correct
13 Correct 2 ms 11868 KB Output is correct
14 Correct 2 ms 11868 KB Output is correct
15 Correct 3 ms 11868 KB Output is correct
16 Correct 3 ms 11868 KB Output is correct
17 Correct 3 ms 11868 KB Output is correct
18 Correct 2 ms 11868 KB Output is correct
19 Correct 205 ms 43344 KB Output is correct
20 Correct 202 ms 37812 KB Output is correct
21 Correct 215 ms 42928 KB Output is correct
22 Correct 188 ms 36036 KB Output is correct
23 Correct 231 ms 42172 KB Output is correct
24 Correct 251 ms 43332 KB Output is correct
25 Correct 173 ms 39876 KB Output is correct
26 Correct 185 ms 34016 KB Output is correct
27 Correct 259 ms 47056 KB Output is correct
28 Correct 216 ms 41920 KB Output is correct
29 Correct 217 ms 41920 KB Output is correct
30 Correct 199 ms 40764 KB Output is correct
31 Correct 218 ms 41664 KB Output is correct
32 Correct 152 ms 40952 KB Output is correct
33 Correct 2 ms 11868 KB Output is correct
34 Correct 2 ms 11868 KB Output is correct
35 Correct 2 ms 12000 KB Output is correct
36 Correct 2 ms 11868 KB Output is correct
37 Incorrect 252 ms 43184 KB Output isn't correct
38 Halted 0 ms 0 KB -