제출 #535833

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
535833		perchuts	Love Polygon (BOI18_polygon)	C++17	75 / 100	307 ms	22604 KiB

polygon

#include <bits/stdc++.h>
#define maxn (int)(1e5+51)
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define ll long long
#define pb push_back
#define ull unsigned long long
#define ii pair<int,int>
#define iii tuple<int,int,int>
#define inf 2000000001
#define mod 1000000007 //998244353
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);

using namespace std;

template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }

map<string,int>mp;
int par[maxn], ans;
vector<int>g[maxn];
int vis[maxn], mark[maxn];


void dfs(int u, int p){
    ckmax(vis[u],1);
    for(auto v:g[u]){
        if(vis[v]!=2)dfs(v,u);
    }
    if(!mark[u]&&u!=p)ans++, mark[p] = 1;
}

int main(){_
    int n;cin>>n;
    if(n&1){
        cout<<-1<<endl;
        return 0;
    }
    int q = 0;
    for(int i=1;i<=n;++i){
        string a,b;cin>>a>>b;
        if(mp.find(a)==mp.end())mp[a]=++q;
        if(mp.find(b)==mp.end())mp[b]=++q;
        int u = mp[a], v = mp[b];
        par[u] = v;
        g[v].pb(u);
    }   
    for(int i=1;i<=n;++i){
        if(!vis[i]){
            int cur = i;
            while(!vis[cur])vis[cur] = 1, cur = par[cur];
            int start = cur, cnt = 1;
            cur = par[cur];
            while(cur!=start){
                vis[cur] = 2, cur = par[cur], ++cnt;
            }
            vis[start] = 2,cur = par[cur];
            if(cnt==2)mark[cur] = mark[par[cur]] = 1;
            dfs(start,start);
            while(cur!=start){
                dfs(cur,cur);
                cur = par[cur];
            }
            if(!mark[start])ans++, mark[par[start]] = 1;
            cur = par[start];
            while(cur!=start){
                if(!mark[cur])ans++, mark[par[cur]] = 1;
                cur = par[cur];
            }
        }
    }   

    cout<<ans<<endl;
}

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