Submission #244680

#	Time	Username	Problem	Language	Result	Execution time	Memory
244680		kimbj0709	Railway (BOI17_railway)	C++14	0 / 100	94 ms	21652 KiB

railway

#include<bits/stdc++.h>
using namespace std;
#define maxn 100050
vector<vector<pair<int,int> > > adj(maxn);
vector<int> cnt(maxn,0);
vector<int> vect1;
vector<int> seg(maxn*12,0);
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);
    if(depth[seg[node*2*2]]>depth[seg[node*2+1]]){
        seg[node] = seg[node*2+1];
    }
    else{
        seg[node] = seg[node*2+2];
    }
}
int query(int node,int start,int end,int rangemin,int rangemax){
    if(start>=rangemin&&end<=rangemax){
        return seg[node];
    }
    if(start>rangemax||end<rangemin){
        return -1;
    }
    int mid = (start+end)/2;
    int left = query(node*2+1,start,mid,rangemin,rangemax);
    int right = query(node*2+2,mid+1,end,rangemin,rangemax);
    if(left==-1){
        return right;
    }
    if(right==-1){
        return left;
    }
    if(depth[right]>depth[left]){
        return left;
    }
    else{
        return right;
    }
}
void dfs(int node,int parent,int d){
    pos[node] = vect1.size();
    vect1.push_back(node);
    depth[node] = d;
    for(auto k:adj[node]){
        if(k.first!=parent){
            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;
    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 >> input1 >> input2;
        assert(no_of_input==2);
        int lca = query(0,0,vect1.size()-1,min(pos[input1],pos[input2]),max(pos[input1],pos[input2]));
        cnt[input1]++;
        cnt[input2]++;
        cnt[lca] -= 2;
    }
    dfs2(1,-1,-1);
    cout << ans.size() << '\n';
    for(auto k:ans){
        cout << k+1 << " ";
    }


}

Compilation message (stderr)

railway.cpp: In function 'int32_t main()':
railway.cpp:76:23: warning: unused variable 'input3' [-Wunused-variable]
     int input1,input2,input3,input;
                       ^~~~~~
railway.cpp:76:30: warning: unused variable 'input' [-Wunused-variable]
     int input1,input2,input3,input;
                              ^~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 7
• Subtask 4: 0 / 29
• Subtask 5: 0 / 16
• Subtask 6: 0 / 25