제출 #377001

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
377001		lertwqen243	Love Polygon (BOI18_polygon)	C++14	0 / 100	196 ms	18192 KiB

polygon

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 5;

int n,love[N];
int ind;
unordered_map<string,int>id;
vector <int> g[N],adj[N];
bool mrk[N];
vector<int>ord,roots;
void dfs(int v){
    mrk[v]=1;
    for (int i=0;i<(int)g[v].size();i++){
        int u=g[v][i];
        if (!mrk[u]){
            adj[v].push_back(u); 
            dfs(u);
        }
    }
    ord.push_back(v);
    return;
}
int used[N];
int max_maching;
bool mark[N];
void maching_dfs(int v, int par){
    for (int i=0;i<(int)adj[v].size();i++){
        int u=adj[v][i];
        maching_dfs(u,v);
    }
    if (!used[v] && !used[par] && par!=0){
        max_maching++;
        used[v]=used[par]=1;
    }
}
inline int solve1(int root){
    max_maching = 0;
    for (int i=0;i<(int)ord.size();i++){
        int v=ord[i];
        used[v]=0;
    }
    maching_dfs(root,0);
    return max_maching;
}
inline int solve2(int root){
    if (love[root]==root) return 0;
    for (int i=0;i<(int)ord.size();i++){
        int v=ord[i];
        used[v]=0;
    }
    used[root]=used[love[root]]=1;
    max_maching=0;
    maching_dfs(root,0);
    return max_maching+1+(int)(love[love[root]]==root);
}
int main() {
    ios_base::sync_with_stdio(0),cin.tie(0);cout.tie(0);
    cin>>n;
    if (n%2){
        cout<<"-1\n";
        return 0;
    }
    for (int i=1;i<=n;i++){
        string a,b;
        cin>>a>>b;
        if (id.count(a)==0){
            id[a]=++ind;
        }
        if (id.count(b)==0){
            id[b]=++ind;
        }
        int u=id[a];
        int v=id[b];
        love[u]=v;
        g[v].push_back(u);
    }
    for (int i=1;i<=n;i++){
        mrk[i]=0;
        if(love[i]==i) roots.push_back(i);
    }
    int ans=n;
    for (int j=0;j<(int)roots.size();j++){
        int i=roots[j];
        int root=i;  
        ord.clear();dfs(root);
        ans-=solve1(root);
    }
    for(int i=1;i<=n;i++){adj[i] = {}; mrk[i]=0;}
    int ans2 = n;
    for(int i=1;i<=n;i++){
        if (mrk[i]) continue;
        int root=i;
        mark[i]=1;
        if (!mark[love[root]]){
            root=love[root];
            mark[root]=1;
        }   
        ord.clear();dfs(root);
        ans-=max(solve2(root),solve1(root));
    }
    assert(ans<ans2);
    cout<<ans<<'\n';
    return 0;
}

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