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Submission #486647

# Submission time Handle Problem Language Result Execution time Memory
486647 2021-11-12T08:17:32 Z FatihSolak Love Polygon (BOI18_polygon) C++17
75 / 100
 301 ms 23188 KB 
#include <bits/stdc++.h>
#define N 200005
using namespace std;
vector<int> adj[N];
int ans = 0;
int edge[N];
bool cycle[N];
int vis[N];
bool del[N];
void dfs(int v){
    vis[v] = 1;
    if(vis[edge[v]] == 1){
        cycle[v] = 1;
        int tmp = edge[v];
        while(tmp != v){
            cycle[tmp] = 1;
            tmp = edge[tmp];
        }
    }
    else if(!vis[edge[v]]){
        dfs(edge[v]);
    }
    vis[v] = 2;
}
void dfs2(int v){
    for(auto u:adj[v]){
        if(cycle[u])continue;
        dfs2(u);
        ans += !del[u];
        if(!del[u]){
            del[v] = del[u] = 1;
        }
    }
}
void solve(){
    int n;
    cin >> n;
    int cnt = 1;
    map<string,int>val;
    for(int i=1;i<=n;i++){
        string s,t;
        cin >> s >> t;
        if(!val[s])val[s] = cnt++;
        if(!val[t])val[t] = cnt++;
        edge[val[s]] = val[t];
        adj[val[t]].push_back(val[s]);
    }
    if(n%2){
        cout << -1 << endl;
        return;
    }
    if(n <= 20){
        int ans = n;
        for(int mask = 0;mask < (1<<(n+1));mask+=2){
            vector<int> go(n+1);
            bool ok = 1;
            for(int i=1;i<=n;i++){
                if(mask & (1<<i)){
                    if(edge[i] == i)ok = 0;
                    if(go[i] && edge[i] != go[i])ok = 0;
                    go[i] = edge[i];
                    if(go[edge[i]] && go[edge[i]] != i)ok = 0;
                    go[edge[i]] = i;
                }
            }
            if(ok)
                ans = min(ans,n - __builtin_popcount(mask));
        }
        cout << ans;
        return;
    }
    for(int i=1;i<=n;i++){
        if(!vis[i]){
            dfs(i);
        }
    }
    /*
    for(auto u:val){
        cout << u.first << " " << u.second << endl;
    }*/
    for(int i=1;i<=n;i++){
        if(cycle[i]){
            dfs2(i);
        }
    }
    /*
    for(auto u:val){
        cout << u.first << " " << del[u.second] << endl;
    }*/
    ///cout << ans << endl;
    for(int i=1;i<=n;i++){
        if(del[i])continue;
        //cout << i << endl;
        vector<int> v;
        int tmp = i;
        while(v.empty() || tmp != i){
            v.push_back(tmp);
            if(!del[edge[tmp]])
                tmp = edge[tmp];
            else break;
        }
        if(tmp == i){
            if(v.size() != 2){
                ans += v.size()/2 + v.size()%2;
            }
            for(auto u:v)del[u] = 1;
            continue;
        }
        int bef = -1;
        for(auto u:adj[i]){
            if(!del[u])bef = u;
        }
        while(bef != -1){
            v.push_back(bef);
            for(auto u:adj[bef]){
                if(!del[u]){
                    bef = u;
                    break;
                }
            }
            if(bef == v.back())bef = -1;
        }
        for(auto u:v)del[u] = 1;
        ans += v.size()/2 + v.size()%2;
    }
    cout << ans;

}

int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    #ifdef Local
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
    #endif
    int t=1;
    //cin>>t;
    while(t--){
        solve();
    }
    #ifdef Local
    cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
    #endif
}

Subtask #1
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 87 ms 5008 KB Output is correct
2 Correct 101 ms 5024 KB Output is correct
3 Correct 94 ms 4940 KB Output is correct
4 Correct 3 ms 4940 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 4 ms 4940 KB Output is correct
7 Correct 89 ms 5012 KB Output is correct
8 Correct 88 ms 5020 KB Output is correct
9 Correct 89 ms 5060 KB Output is correct
10 Correct 89 ms 4940 KB Output is correct
11 Correct 94 ms 5016 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 4940 KB Output is correct
15 Correct 3 ms 4940 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 5000 KB Output is correct
2 Correct 3 ms 4928 KB Output is correct
3 Correct 3 ms 4940 KB Output is correct
4 Correct 275 ms 20740 KB Output is correct
5 Correct 257 ms 17492 KB Output is correct
6 Correct 263 ms 21156 KB Output is correct
7 Correct 239 ms 16864 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 280 ms 16728 KB Output is correct
2 Correct 251 ms 18480 KB Output is correct
3 Correct 204 ms 17504 KB Output is correct
4 Correct 233 ms 15480 KB Output is correct
5 Correct 267 ms 23188 KB Output is correct
6 Correct 240 ms 15880 KB Output is correct
7 Correct 301 ms 16028 KB Output is correct
8 Correct 239 ms 16324 KB Output is correct
9 Correct 234 ms 15452 KB Output is correct
10 Correct 174 ms 14660 KB Output is correct
11 Correct 8 ms 5020 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 7 ms 5020 KB Output is correct

Subtask #4
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 87 ms 5008 KB Output is correct
2 Correct 101 ms 5024 KB Output is correct
3 Correct 94 ms 4940 KB Output is correct
4 Correct 3 ms 4940 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 4 ms 4940 KB Output is correct
7 Correct 89 ms 5012 KB Output is correct
8 Correct 88 ms 5020 KB Output is correct
9 Correct 89 ms 5060 KB Output is correct
10 Correct 89 ms 4940 KB Output is correct
11 Correct 94 ms 5016 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 4940 KB Output is correct
15 Correct 3 ms 4940 KB Output is correct
16 Correct 4 ms 5000 KB Output is correct
17 Correct 3 ms 4928 KB Output is correct
18 Correct 3 ms 4940 KB Output is correct
19 Correct 275 ms 20740 KB Output is correct
20 Correct 257 ms 17492 KB Output is correct
21 Correct 263 ms 21156 KB Output is correct
22 Correct 239 ms 16864 KB Output is correct
23 Correct 280 ms 16728 KB Output is correct
24 Correct 251 ms 18480 KB Output is correct
25 Correct 204 ms 17504 KB Output is correct
26 Correct 233 ms 15480 KB Output is correct
27 Correct 267 ms 23188 KB Output is correct
28 Correct 240 ms 15880 KB Output is correct
29 Correct 301 ms 16028 KB Output is correct
30 Correct 239 ms 16324 KB Output is correct
31 Correct 234 ms 15452 KB Output is correct
32 Correct 174 ms 14660 KB Output is correct
33 Correct 8 ms 5020 KB Output is correct
34 Correct 3 ms 4940 KB Output is correct
35 Correct 3 ms 4940 KB Output is correct
36 Correct 7 ms 5020 KB Output is correct
37 Incorrect 261 ms 16592 KB Output isn't correct
38 Halted 0 ms 0 KB -