Submission #70881

#	Time	Username	Problem	Language	Result	Execution time	Memory
70881		aquablitz11	Toy Train (IOI17_train)	C++14	100 / 100	892 ms	15760 KiB

train

#include <bits/stdc++.h>
#include "train.h"
using namespace std;
 
using pii = pair<int, int>;
 
const int N = 5e3+10;

vector<int> G[N], R[N];
int need[N];
bool win[N];

void dfs(int u, int r=0) {
    need[u] = 0;
    if (!r) win[u] = true;
    for (auto v : R[u]) if (--need[v] == 0)
        dfs(v, r);
}

vector<int> who_wins(vector<int> A, vector<int> C, vector<int> U, vector<int> V)
{
    int n = A.size();
    int m = U.size();
    for (int i = 0; i < m; ++i) {
        G[U[i]].push_back(V[i]);
        R[V[i]].push_back(U[i]);
    }

    while (true) {
        // find all nodes that A can force to charger
        for (int u = 0; u < n; ++u)
            win[u] = false, need[u] = A[u] ? 1 : (int)G[u].size();
        for (int u = 0; u < n; ++u) if (C[u] && need[u] > 0)
            dfs(u);
        // for nodes that A can't force, find which nodes B could force movement from
        for (int u = 0; u < n; ++u)
            need[u] = A[u] ? (int)G[u].size() : 1;
        for (int u = 0; u < n; ++u) if (!win[u] && need[u] > 0)
            dfs(u, 1);
        // if B could win on some charger, remove charger
        bool mod = false;
        for (int u = 0; u < n; ++u) if (need[u] <= 0 && C[u])
            C[u] = false, mod = true;
        if (!mod) break;
    }

    vector<int> ans(n);
    for (int u = 0; u < n; ++u) if (need[u] > 0)
        ans[u] = 1;
    return ans;
}

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