Submission #713532

#	Time	Username	Problem	Language	Result	Execution time	Memory
713532		MohamedFaresNebili	Toy Train (IOI17_train)	C++14	11 / 100	1286 ms	99420 KiB

train

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
 
        using namespace std;
        using namespace __gnu_pbds;
 
        using ll = long long;
        using ii = pair<int, int>;
 
        #define pb push_back
        #define pp pop_back
        #define ff first
        #define ss second
 
        typedef tree<int, null_type, less<int>, rb_tree_tag,
            tree_order_statistics_node_update> indexed_set;
 
        int N, M, timer, tin[5001], low[5001];
        vector<int> adj[5001], S;
        bool vis[5001], Scc[5001], station[5001];
        bool self[5001];
        int DP[5001][5001];
 
        void dfs(int v) {
            tin[v] = low[v] = timer++;
            S.push_back(v); vis[v] = 1;
            for(auto u : adj[v]) {
                if(tin[u] == -1) dfs(u);
                if(vis[u]) low[v] = min(low[v], low[u]);
            }
            if(tin[v] == low[v]) {
                vector<int> V; bool valid = 0;
                while(1) {
                    int U = S.back(); S.pop_back();
                    V.push_back(U); vis[U] = 0;
                    if(station[U]) valid = 1;
                    if(U == v) break;
                }
                if(V.size() == 1) return;
                for(auto u : V)
                    Scc[u] = valid;
            }
        }
        int solve(int v, int t) {
            if(Scc[v]) return 1;
            if(DP[v][t] != -1) return DP[v][t];
            if(t) {
                for(auto u : adj[v]) {
                    if(solve(u, t - 1))
                        return DP[v][t] = 1;
                }
            }
            if(station[v] && adj[v].size() == 0)
                return DP[v][t] = 1;
            return DP[v][t] = 0;
        }
        int solve(int v, int t, vector<int> A) {
            if(v >= N) return 0;
            if(station[v]) t = N;
            if(A[v] == 1) {
                if(station[v] && self[v])
                    return 1;
                for(auto u : adj[v]) {
                    if(solve(v + 1, t - 1, A))
                        return 1;
                }
                return 0;
            }
            if(station[v]) {
                for(auto u : adj[v]) 
                  return solve(v + 1, t - 1, A);
              	return 0;
            }
            if(self[v]) return 0;
          	return solve(v + 1, t - 1, A);
        }
        vector<int> subtask1(vector<int> A) {
            vector<int> res(N, 0);
            for(int l = 0; l < N; l++) {
                res[l] = solve(l, N, A);
            }
            return res;
        }
 
        vector<int> who_wins(vector<int> A, vector<int> R,
                             vector<int> U, vector<int> V) {
            N = A.size(), M = U.size();
            for(int l = 0; l < N; l++)
                station[l] = R[l];
            bool ok = 1;
            for(int l = 0; l < M; l++) {
                int u = U[l], v = V[l];
                if(u == v) {
                    Scc[u] = station[u];
                    self[u] = 1; continue;
                }
                adj[u].pb(v); ok &= (v == u + 1);
            }
            if(ok) return subtask1(A);
            memset(tin, -1, sizeof tin);
            memset(DP, -1, sizeof DP);
            for(int l = 0; l < N; l++) {
                if(tin[l] != -1) continue;
                dfs(l);
            }
            vector<int> res(N);
            for(int l = 0; l < N; l++) {
                res[l] = solve(l, N);
            }
            return res;
        }

Compilation message (stderr)

train.cpp: In function 'int solve(int, int, std::vector<int>)':
train.cpp:63:26: warning: unused variable 'u' [-Wunused-variable]
   63 |                 for(auto u : adj[v]) {
      |                          ^
train.cpp:70:26: warning: unused variable 'u' [-Wunused-variable]
   70 |                 for(auto u : adj[v])
      |                          ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 11 / 11
• Subtask 4: 0 / 11
• Subtask 5: 0 / 12
• Subtask 6: 0 / 51