Submission #948650

#	Time	Username	Problem	Language	Result	Execution time	Memory
948650		JakobZorz	Bitaro’s Party (JOI18_bitaro)	C++17	14 / 100	2062 ms	420136 KiB

bitaro

#include<iostream>
#include<vector>
#include<queue>
#include<stack>
#include<algorithm>
#include<limits.h>
#include<math.h>
#include<map>
#include<set>
#include<unordered_map>
#include<unordered_set>
#include<iomanip>
#include<cstring>
#include<random>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
using namespace std;

int n,m,q;
vector<int>nodes[100000];
vector<int>rev[100000];
vector<pair<int,int>>farthest[100000]; // (dist,node)

const int CHUNK_SIZE=300;

int solve(int src,vector<int>blocked){
    vector<int>in(n);
    vector<int>res(n);
    queue<int>q;
    for(int i=0;i<n;i++){
        in[i]=(int)rev[i].size();
        if(in[i]==0)
            q.push(i);
    }
    for(int i:blocked)
        res[i]=-1e9;
    while(q.size()){
        int node=q.front();
        q.pop();
        for(int ne:rev[node])
            res[node]=max(res[node],res[ne]+1);
        for(int ne:nodes[node]){
            in[ne]--;
            if(in[ne]==0)
                q.push(ne);
        }
    }
    return max(-1,res[src]);
}

void setup(){
    vector<int>in(n);
    queue<int>q;
    for(int i=0;i<n;i++){
        in[i]=(int)rev[i].size();
        if(in[i]==0)
            q.push(i);
    }
    while(q.size()){
        int node=q.front();
        q.pop();
        vector<int>it(rev[node].size());
        while(farthest[node].size()<CHUNK_SIZE){
            int nxt=-1;
            for(int i=0;i<(int)it.size();i++){
                if(it[i]==(int)farthest[rev[node][i]].size())
                    continue;
                
                if(nxt==-1||farthest[rev[node][i]][it[i]].first>farthest[rev[node][nxt]][it[nxt]].first)
                    nxt=i;
            }
            
            if(nxt==-1)
                break;
                
            farthest[node].push_back(farthest[rev[node][nxt]][it[nxt]]);
            farthest[node].back().first++;
            it[nxt]++;
        }
        
        if(farthest[node].size()<CHUNK_SIZE)
            farthest[node].emplace_back(0,node);
        
        for(int ne:nodes[node]){
            in[ne]--;
            if(in[ne]==0)
                q.push(ne);
        }
    }
}

void solve(){
    cin>>n>>m>>q;
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a>>b;
        a--;b--;
        nodes[a].push_back(b);
        rev[b].push_back(a);
    }
    setup();
    while(q--){
        int src,k;
        cin>>src>>k;
        src--;
        vector<int>blocked(k);
        for(int&i:blocked){
            cin>>i;
            i--;
        }
        unordered_set<int>s(blocked.begin(),blocked.end());
        int res=-1;
        for(auto[d,i]:farthest[src]){
            if(s.count(i)==0){
                res=d;
                break;
            }
        }
        if(res!=-1||farthest[src].size()!=CHUNK_SIZE){
            cout<<res<<"\n";
            continue;
        }
        
        cout<<solve(src,blocked)<<"\n";
    }
}

int main(){
    ios::sync_with_stdio(false);cout.tie(NULL);cin.tie(NULL);
    //freopen("/Users/jakob/cp_testing/test.txt","r",stdin);//freopen("output.out","w",stdout);
    int t=1;//cin>>t;
    while(t--)solve();
    return 0;
}


/*

5 6 3
1 2
2 4
3 4
1 3
3 5
4 5
4 1 1
5 2 2 3
2 3 1 4 5
 
 
1
3
0

 */

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 0 / 86