Submission #1076802

#	Time	Username	Problem	Language	Result	Execution time	Memory
1076802		zehnsechs	Toy Train (IOI17_train)	C++14	100 / 100	258 ms	1880 KiB

train

#include "train.h"
#include<bits/stdc++.h>

using namespace std;


void dfs(int v, vector<int>& x, vector<int>& c, vector<vector<int>>& adj, vector<int>& res){
    if(res[v]) return;
    res[v]=1;
    //cerr << "vertex " << v << '\n';    
    if(res[v]){
        for(int u: adj[v]){
            //cerr << "n " << u << '\n';
            if (u==v) continue;
            c[u]--;
            if(c[u]==0 && !res[u]) {
                dfs(u,x,c,adj,res);
            }
        }
    }
}


vector<int> who_wins(vector<int> a, vector<int> r, vector<int> u, vector<int> v) {
	int n = a.size();
        int m = u.size();
        vector<int> res(n,1);
        vector<vector<int>> adj(n);
        vector<int> deg(n,0);
        
        //add the edges to adj in the opposite direction
        for(int i=0;i<m;++i){
            //cerr << "edge " << u[i] << ' ' << v[i] << '\n';
            adj[v[i]].push_back(u[i]);
            deg[u[i]]++;
        }
        
        bool con = true;
        while(con){
            con = false;
            vector<int> fa(n,0);
            vector<int> rm(n,0);
            vector<int> c0(n,1);
            vector<int> c1(n,1);
            
            for(int i=0;i<n;++i) (a[i] ? c1[i] = deg[i] : c0[i]= deg[i]);
            //cerr << "fa" << '\n';
            for(int i=0;i<n;++i) if(r[i]&&res[i]) dfs(i,r,c0,adj,fa);
            vector<int> x(n,0);
            for(int i=0;i<n;++i) if(!fa[i]) x[i]=1;
            //cerr << "fb" << '\n';
            
            for(int i=0;i<n;++i) if(!fa[i]&&res[i]) dfs(i,x,c1,adj,rm);
            for(int i=0;i<n;++i) if(rm[i]) {
                //cerr << "unreachable " << i <<'\n';
                for(int u: adj[i]) deg[u]--;
                adj[i].clear();
                res[i]=0;
                con = true;
                }
        }



	return res;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 11 / 11
• Subtask 4: 11 / 11
• Subtask 5: 12 / 12
• Subtask 6: 51 / 51