Submission #1055022

#	Time	Username	Problem	Language	Result	Execution time	Memory
1055022		Wansur	Toy Train (IOI17_train)	C++17	100 / 100	168 ms	1756 KiB

train

#include <bits/stdc++.h>
#include "train.h"
#define ent '\n'
#define  f first
#define s second
//#define int long long

using namespace std;
typedef long long ll;
const int maxn = 5e3 + 12;
const int mod = 1e9 + 7;

vector<int> g[maxn], rg[maxn];
bool won[maxn], del[maxn];
int out[maxn];
int n, m;

vector<int> who_wins(vector<int> a, vector<int> r, vector<int> U, vector<int> V){
    n = a.size(), m = U.size();
    vector<int> ans(n);

    for(int i=0;i<m;i++){
        g[U[i]].push_back(V[i]);
        rg[V[i]].push_back(U[i]);
    }

    bool ok = 0;

    while(true){
        for(int i=0;i<n;i++){
            out[i] = g[i].size();
            won[i] = 0;
        }

        queue<int> q;

        for(int i=0;i<n;i++){
            won[i] = 0;
            if(r[i] == 1){
                won[i] = 1;
                q.push(i);
            }
        }

        while(q.size()){
            int v = q.front();
            q.pop();
            for(int to:rg[v]){
                if(a[to] && !won[to]){
                    won[to] = 1;
                    q.push(to);
                }
                if(!a[to] && !won[to]){
                    out[to]--;
                    if(out[to] == 0){
                        won[to] = 1;
                        q.push(to);
                    }
                }
            }
        }

        bool fg = 1;

        for(int i=0;i<n;i++){
            if(r[i]){
                bool ok = 1 - a[i];
                for(int to:g[i]){
                    if(a[i]) ok |= won[to];
                    else ok &= won[to];
                }
                fg &= ok;
                if(!ok) {
                    r[i] = 0;
                }
            }
        }

        if(fg){
            for(int i=0;i<n;i++){
                ans[i] |= won[i];
            }
            break;
        }
    }
    
    return ans;
}

Compilation message (stderr)

train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:27:10: warning: unused variable 'ok' [-Wunused-variable]
   27 |     bool ok = 0;
      |          ^~

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