Submission #254983

#	Time	Username	Problem	Language	Result	Execution time	Memory
254983		kimbj0709	Village (BOI20_village)	C++14	100 / 100	184 ms	21156 KiB

Village

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define maxn 100050
#define f first
#define s second
vector<vector<int> > adj(maxn);
vector<int> subtree_size(maxn,0);
vector<int> pos(maxn,0);
int currcnt = 1;
int n,input1,input2;
int centroid = 0;
void dfs1(int node,int parent){//used to find subtree size
    subtree_size[node] = 1;
    pos[node] = currcnt;
    currcnt++;
    for(auto k:adj[node]){
        if(k==parent){
            continue;
        }
        dfs1(k,node);
        subtree_size[node] += subtree_size[k];
    }
    return;
}
vector<int> reroute(maxn,1);
int mindist = 0;
void dfs2(int node,int parent){//used to find optimal ordering
    for(auto k:adj[node]){
        if(k==parent){
            continue;
        }
        dfs2(k,node);
    }
    if(reroute[node]==node&&parent!=-1){
        swap(reroute[node],reroute[parent]);
        mindist++;
    }
    if(reroute[node]==node&&parent==-1){
        swap(reroute[node],reroute[adj[node][0]]);
        mindist++;
    }
    return;
}
vector<int> dist(maxn,0);
void dfs3(int node,int parent,int distt){
    dist[node] = distt;
    for(auto k:adj[node]){
        if(k!=parent){
            dfs3(k,node,distt+1);
        }
    }
}
void dfs4(int node,int parent){
    bool can = 1;
    for(auto k:adj[node]){
        if(k!=parent){
            dfs4(k,node);
            if(subtree_size[k]>(n/2)){
                can = 0;
            }
        }
    }
    if(n-subtree_size[node]>(n/2)){
        can = 0;
    }
    if(can){
        centroid = node;
    }
}
int maxdist = 0;
void dfs5(int node,int parent){
    for(auto k:adj[node]){
        if(k!=parent){
            dfs5(k,node);
            maxdist += subtree_size[k];
        }
    }
}
vector<int> nodes(maxn);
vector<int> ipos(maxn*2);
int position = 0;
void dfs6(int node,int parent){
    ipos[position] = node;
    ipos[position+n] = node;
    nodes[node] = position; 
    position++;
    for(auto k:adj[node]){
        if(k!=parent){
            dfs6(k,node);
        }
    }
}
vector<int> arrangement(maxn,0);
int32_t main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    for(int i=0;i<maxn;i++){
        reroute[i] = i;
    }
    cin >> n;
    for(int i=0;i<n-1;i++){
        cin >> input1 >> input2;
        adj[input1].push_back(input2);
        adj[input2].push_back(input1);
    }
    int root = -1;
    for(int i=1;i<=n;i++){
        if(adj[i].size()==(int)1){
            root = i;
        }
    }
    dfs1(root,-1);
    dfs2(root,-1);
    dfs4(root,-1);
    dfs1(centroid,-1);
    dfs5(centroid,-1);
    int tt = 0;
    dfs6(centroid,-1);
    for(int i=1;i<=n;i++){
      arrangement[ipos[nodes[i]+(n/2)]] = i;
    }
    
    cout << mindist*2 << " " << maxdist*2 << "\n";
    for(int i=1;i<=n;i++){
        cout << reroute[i] << " ";
        //cout << i << " ";
    }
    cout << "\n";
    for(int i=1;i<=n;i++){
        //cout << 1 << " ";
        cout << arrangement[i] << ' ';
        //cout << i << " ";
    }
 
}

Compilation message (stderr)

Village.cpp: In function 'int32_t main()':
Village.cpp:118:9: warning: unused variable 'tt' [-Wunused-variable]
     int tt = 0;
         ^~

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