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Submission #486646

# Submission time Handle Problem Language Result Execution time Memory
486646 2021-11-12T08:15:49 Z FatihSolak Love Polygon (BOI18_polygon) C++17
75 / 100
 2000 ms 1033428 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;
                }
            }
        }
        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 124 ms 4940 KB Output is correct
2 Correct 105 ms 4940 KB Output is correct
3 Correct 91 ms 4940 KB Output is correct
4 Correct 3 ms 4940 KB Output is correct
5 Correct 2 ms 4940 KB Output is correct
6 Correct 2 ms 4940 KB Output is correct
7 Correct 96 ms 5004 KB Output is correct
8 Correct 111 ms 4940 KB Output is correct
9 Correct 94 ms 5016 KB Output is correct
10 Correct 91 ms 4940 KB Output is correct
11 Correct 93 ms 5004 KB Output is correct
12 Correct 2 ms 4940 KB Output is correct
13 Correct 2 ms 4940 KB Output is correct
14 Correct 2 ms 4940 KB Output is correct
15 Correct 2 ms 4940 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4940 KB Output is correct
2 Correct 2 ms 4940 KB Output is correct
3 Correct 3 ms 4940 KB Output is correct
4 Correct 268 ms 20120 KB Output is correct
5 Correct 233 ms 16872 KB Output is correct
6 Correct 254 ms 20544 KB Output is correct
7 Correct 224 ms 16324 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 256 ms 16200 KB Output is correct
2 Correct 294 ms 17688 KB Output is correct
3 Correct 190 ms 16944 KB Output is correct
4 Correct 242 ms 14788 KB Output is correct
5 Correct 236 ms 22628 KB Output is correct
6 Correct 247 ms 15304 KB Output is correct
7 Correct 227 ms 15432 KB Output is correct
8 Correct 208 ms 15684 KB Output is correct
9 Correct 230 ms 14812 KB Output is correct
10 Correct 170 ms 14012 KB Output is correct
11 Correct 11 ms 5016 KB Output is correct
12 Correct 2 ms 5016 KB Output is correct
13 Correct 2 ms 4940 KB Output is correct
14 Correct 7 ms 4940 KB Output is correct

Subtask #4
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 124 ms 4940 KB Output is correct
2 Correct 105 ms 4940 KB Output is correct
3 Correct 91 ms 4940 KB Output is correct
4 Correct 3 ms 4940 KB Output is correct
5 Correct 2 ms 4940 KB Output is correct
6 Correct 2 ms 4940 KB Output is correct
7 Correct 96 ms 5004 KB Output is correct
8 Correct 111 ms 4940 KB Output is correct
9 Correct 94 ms 5016 KB Output is correct
10 Correct 91 ms 4940 KB Output is correct
11 Correct 93 ms 5004 KB Output is correct
12 Correct 2 ms 4940 KB Output is correct
13 Correct 2 ms 4940 KB Output is correct
14 Correct 2 ms 4940 KB Output is correct
15 Correct 2 ms 4940 KB Output is correct
16 Correct 2 ms 4940 KB Output is correct
17 Correct 2 ms 4940 KB Output is correct
18 Correct 3 ms 4940 KB Output is correct
19 Correct 268 ms 20120 KB Output is correct
20 Correct 233 ms 16872 KB Output is correct
21 Correct 254 ms 20544 KB Output is correct
22 Correct 224 ms 16324 KB Output is correct
23 Correct 256 ms 16200 KB Output is correct
24 Correct 294 ms 17688 KB Output is correct
25 Correct 190 ms 16944 KB Output is correct
26 Correct 242 ms 14788 KB Output is correct
27 Correct 236 ms 22628 KB Output is correct
28 Correct 247 ms 15304 KB Output is correct
29 Correct 227 ms 15432 KB Output is correct
30 Correct 208 ms 15684 KB Output is correct
31 Correct 230 ms 14812 KB Output is correct
32 Correct 170 ms 14012 KB Output is correct
33 Correct 11 ms 5016 KB Output is correct
34 Correct 2 ms 5016 KB Output is correct
35 Correct 2 ms 4940 KB Output is correct
36 Correct 7 ms 4940 KB Output is correct
37 Execution timed out 2188 ms 1033428 KB Time limit exceeded
38 Halted 0 ms 0 KB -