Submission #246287

#	Time	Username	Problem	Language	Result	Execution time	Memory
246287		kimbj0709	Railway (BOI17_railway)	C++14	100 / 100	190 ms	27008 KiB

railway

#include<bits/stdc++.h>
using namespace std;
#define maxn 100050
#define f first
#define s second
vector<vector<pair<int,int> > > adj(maxn);
vector<int> cnt(maxn,0);
vector<int> vect1;
vector<int> seg(maxn*20,0);
vector<int> depth(maxn,INT_MAX);
vector<int> pos(maxn);
int no_of_vertex,no_of_people,mini;
void build(int node,int start,int end){
    if(start==end){
        seg[node] = vect1[start];
        return;
    }
    int mid = (start+end)/2;
    build(node*2+1,start,mid);
    build(node*2+2,mid+1,end);
    int l = seg[node*2+1];
    int r = seg[node*2+2];
    if(l==-1){
      seg[node] = r;
      return;
    }
    if(r==-1){
      seg[node] = l;
      return;
    }
    if(depth[r]<depth[l]){
        seg[node] = r;
    }
    else{
        seg[node] = l;
    }
}
int query(int node,int start,int end,int rangemin,int rangemax){
  //cout << node << " " << start << " " << end << " "<< rangemin << " " << rangemax << " " << seg[node] << endl;
  if(start>rangemax||end<rangemin){
    return -1;
  }
  if(start>=rangemin&&end<=rangemax){
    return seg[node];
  }
  int mid = (start+end)/2;
  int a = query(node*2+1,start,mid,rangemin,rangemax);
  int b = query(node*2+2,mid+1,end,rangemin,rangemax);
  if(a==-1){
    return b;
  }
  else if(b==-1){
    return a;
  }
  if(depth[a]<depth[b]){
    return a;
  }
  else{
    return b;
  }
}
void dfs(int node,int parent,int d){
    pos[node] = (int)vect1.size();
    vect1.push_back(node);
    depth[node] = d;
    for(auto k:adj[node]){
        if(k.first!=parent){
            vect1.push_back(node);
            dfs(k.first,node,d+1);
            //vect1.push_back(node);
        }
    }
}
vector<int> ans;
void dfs2(int node,int parent,int last){
    for(auto k:adj[node]){
        if(k.first!=parent){
            dfs2(k.first,node,k.second);
            cnt[node] += cnt[k.first];
        }
    }
    if(cnt[node]>=mini){
        ans.push_back(last);
    }
}
int32_t main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int no_of_input;
    int input1,input2,input3,input;
    cin >> no_of_vertex >> no_of_people >> mini;
    mini *= 2;
    for(int i=0;i<no_of_vertex-1;i++){
        cin >> input1 >> input2;
        adj[input1].push_back({input2,i});
        adj[input2].push_back({input1,i});
    }
    dfs(1,-1,0);
    build(0,0,vect1.size()-1);
    for(int i=0;i<no_of_people;i++){
        cin >> no_of_input;
        vector<pair<int,int> > temp;
        for(int j=0;j<no_of_input;j++){
          cin >> input1;
          temp.push_back({pos[input1],input1});
        }
        sort(temp.begin(),temp.end());
        for(int j=0;j<no_of_input;j++){
          int small = min(temp[j].f,temp[(j+1)%no_of_input].f);
          int big = max(temp[j].f,temp[(j+1)%no_of_input].f);
          int lca = query(0,0,vect1.size()-1,small,big);
          //cout << lca << "--\n";
          cnt[lca] -= 2;
          cnt[temp[j].s]++;
          cnt[temp[(j+1)%no_of_input].s]++;
        }
    }
    dfs2(1,-1,-1);
    sort(ans.begin(),ans.end());
    cout << ans.size() << '\n';
    for(auto k:ans){
        cout << k+1 << " ";
    }
 
 
}

Compilation message (stderr)

railway.cpp: In function 'int32_t main()':
railway.cpp:90:23: warning: unused variable 'input3' [-Wunused-variable]
     int input1,input2,input3,input;
                       ^~~~~~
railway.cpp:90:30: warning: unused variable 'input' [-Wunused-variable]
     int input1,input2,input3,input;
                              ^~~~~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25