Submission #914921

#	Time	Username	Problem	Language	Result	Execution time	Memory
914921		asdasdqwer	Village (BOI20_village)	C++14	0 / 100	1 ms	348 KiB

Village

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

#define int int64_t


signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;cin>>n;
    vector<set<int>> g(n);
    vector<vector<int>> bck(n);
    vector<int> dg(n,0);
    for (int i=1;i<n;i++) {
        int a,b;cin>>a>>b;a--;b--;
        g[a].insert(b);
        g[b].insert(a);
        bck[a].push_back(b);
        bck[b].push_back(a);
        dg[a]++;dg[b]++;
    }

    queue<int> q;
    vector<bool> vis(n, false);
    for (int i=0;i<n;i++) {
        if (dg[i]==1){
            q.push(i);
            vis[i]=true;
        }
    }

    int ans=0;
    vector<int> conf(n,0);
    for (int i=0;i<n;i++) {
        conf[i]=i;
    }

    vector<bool> swp(n, false);

    while (!q.empty()) {
        int t=q.front();q.pop();
        // cout<<t<<"\n";
        cout.flush();
        if (g[t].size() == 0) {
            if (!swp[conf[t]]) {
                swap(conf[t], conf[bck[t][0]]);
                swp[conf[t]]=true;
                // cout<<conf[t]+1<<" "<<conf[bck[t][0]]+1<<" bb\n";
                ans += 2;
            }
            continue;
        }

        int ne = *g[t].begin();
        vis[ne]=true;

        if (g[ne].find(t) != g[ne].end()) g[ne].erase(g[ne].find(t));
        for (int x:g[ne]) {
            if (g[x].find(ne) != g[x].end()) g[x].erase(g[x].find(ne));
            dg[x]--;
            if (dg[x]<=1 && !vis[x]) {
                q.push(x);
                vis[x]=true;
            }
        }
        if (!swp[ne] && !swp[t]) {
            dg[ne]--;
            ans+=2;
            swap(conf[ne], conf[t]);
            swp[ne]=swp[t]=true;
            // cout<<conf[ne]+1<<" "<<conf[t]+1<<"\n";
        }
    }

    cout<<ans<<"\n";
    for (int x:conf) {
        cout<<x+1<<" ";
    }
    cout<<"\n";
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 38
• Subtask 3: 0 / 50