Submission #707920

#	Time	Username	Problem	Language	Result	Execution time	Memory
707920		Cyanmond	Toy Train (IOI17_train)	C++17	39 / 100	2096 ms	224876 KiB

train

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

using namespace std;

std::vector<int> who_wins(std::vector<int> a, std::vector<int> r, std::vector<int> u, std::vector<int> v) {
    const int n = (int)a.size(), m = (int)u.size();
    std::vector<std::vector<int>> graph(n);
    for (int i = 0; i < m; ++i) {
        graph[u[i]].push_back(v[i]);
    }
    int cntC = 0;
    int chargingS = -1;
    for (int i = 0; i < n; ++i) {
        if (r[i] == 1) {
            ++cntC;
            if (chargingS == -1) {
                chargingS = i;
            }
        }
    }
    if (cntC == 1) {
        // subtask 5
        std::vector<int> reachableV(n, -1);
        reachableV[chargingS] = 1;
        for (int i = 0; i < n; ++i) {
            auto itr = std::find(graph[i].begin(), graph[i].end(), i);
            if (r[i] == 0 and a[i] == 0 and itr != graph[i].end()) {
                reachableV[i] = 0;
            }
        }
        for (int x = 0; x < 2 * n; ++x) {
            for (int i = 0; i < n; ++i) {
                if (reachableV[i] != -1) {
                    continue;
                }
                if (a[i] == 1) {
                    bool isOk = false, isRa = true;
                    for (const int t : graph[i]) {
                        if (reachableV[t] == 1) {
                            isOk = true;
                        }
                        if (reachableV[t] == -1) {
                            isRa = false;
                        }
                    }
                    if (isOk) {
                        reachableV[i] = 1;
                    } else if (isRa) {
                        reachableV[i] = 0;
                    }
                } else {
                    bool isOk = true, isRa = true;
                    for (const int t : graph[i]) {
                        if (reachableV[t] != 1) {
                            isOk = false;
                        }
                        if (reachableV[t] == -1) {
                            isRa = false;
                        }
                    }
                    if (isOk) {
                        reachableV[i] = 1;
                    } else if (isRa) {
                        reachableV[i] = 0;
                    }
                }
            }
        }
        for (auto &e : reachableV) {
            if (e == -1) {
                e = 0;
            }
        }
        reachableV[chargingS] = -1;
        if (a[chargingS] == 1) {
            bool isOk = false;
            for (const int t : graph[chargingS]) {
                if (reachableV[t] == 1) {
                    isOk = true;
                } else if (t == chargingS) {
                    isOk = true;
                }
            }
            if (isOk) {
                reachableV[chargingS] = 1;
            } else {
                reachableV[chargingS] = 0;
            }
        } else {
            bool isOk = true;
            for (const int t : graph[chargingS]) {
                if (reachableV[t] == 0) {
                    isOk = false;
                }
            }
            if (isOk) {
                reachableV[chargingS] = 1;
            } else {
                reachableV[chargingS] = 0;
            }
        }
    
        std::vector<int> answer(n);
        for (int i = 0; i < n; ++i) {
            answer[i] = (reachableV[i] == 1 and reachableV[chargingS] == 1) ? 1 : 0;
        }
        return answer;
    } else if (std::all_of(a.begin(), a.end(), [](const int v) {
        return v == 0;
    })) {
        // subtask 4
        std::vector<int> answer(n, 1);
        std::vector<bool> tCycle(n);
        for (int f = 0; f < n; ++f) {
            std::vector<int> type(n);
            auto dfs = [&](auto &&self, const int v) -> bool {
                type[v] = 1;
                for (const int t : graph[v]) {
                    if (r[t] == 1) {
                        continue;
                    }
                    if (type[t] == 0) {
                        const auto res = self(self, t);
                        if (res) {
                            return true;
                        }
                    } else if (type[t] == 1) {
                        return true;
                    }
                }
                type[v] = 2;
                return false;
            };
            tCycle[f] = dfs(dfs, f);
        }
        std::vector<std::vector<bool>> isReachable(n, std::vector<bool>(n));
        for (int f = 0; f < n; ++f) {
            isReachable[f][f] = true;
            std::queue<int> que;
            que.push(f);
            while (not que.empty()) {
                const int x = que.front();
                que.pop();
                for (const int t : graph[x]) {
                    if (not isReachable[f][t]) {
                        isReachable[f][t] = true;
                        que.push(t);
                    }
                }
            }
        }
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                if (isReachable[i][j] and tCycle[j]) {
                    answer[i] = 0;
                }
            }
        }
        return answer;
    } else if (std::all_of(a.begin(), a.end(), [](const int v) {
        return v == 1;
    })) {
        // subtask 3
        std::vector<int> answer(n);
        std::vector<bool> tCycle(n);
        for (int f = 0; f < n; ++f) {
            if (r[f] == 0) {
                continue;
            }
            std::vector<int> type(n);
            auto dfs = [&](auto &&self, const int v) -> bool {
                type[v] = 1;
                for (const int t : graph[v]) {
                    if (type[t] == 0) {
                        const auto res = self(self, t);
                        if (res) {
                            return true;
                        }
                    } else if (t == f) {
                        return true;
                    }
                }
                type[v] = 2;
                return false;
            };
            tCycle[f] = dfs(dfs, f);
        }
        std::vector<std::vector<bool>> isReachable(n, std::vector<bool>(n));
        for (int f = 0; f < n; ++f) {
            isReachable[f][f] = true;
            std::queue<int> que;
            que.push(f);
            while (not que.empty()) {
                const int x = que.front();
                que.pop();
                for (const int t : graph[x]) {
                    if (not isReachable[f][t]) {
                        isReachable[f][t] = true;
                        que.push(t);
                    }
                }
            }
        }
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                if (isReachable[i][j] and tCycle[j]) {
                    answer[i] = 1;
                }
            }
        }
        return answer;
    } else if (n <= 15) {
        // subtask 2
        std::vector<int> pow3(n + 1);
        pow3[0] = 1;
        for (int i = 1; i <= n; ++i) {
            pow3[i] = pow3[i - 1] * 3;
        }
        std::vector<int> graphBit(n);
        for (int i = 0; i < n; ++i) {
            int b = 0;
            for (const int t : graph[i]) {
                b |= 1 << t;
            }
            graphBit[i] = b;
        }
        std::vector<std::vector<char>> dp(n, std::vector<char>(pow3[n]));
        
        for (int bits = pow3[n] - 1; bits >= 0; --bits) {
            std::vector<int> status(n);
            int bit1 = 0, bit2 = 0, bit3 = 0, bit4 = 0;
            int qbits = bits;
            auto nextBits = [&](const int a) {
                assert(status[a] == 0);
                int res = bits;
                res += pow3[a];
                if (r[a] == 1) {
                    res = qbits + 2 * pow3[a];
                }
                return res;
            };
            for (int i = 0; i < n; ++i) {
                const int v = bits % pow3[i + 1];
                const int c = v / pow3[i];
                status[i] = c;
            }
            for (int i = 0; i < n; ++i) {
                if (status[i] == 1) {
                    qbits += pow3[i];
                }
            }
            for (int i = 0; i < n; ++i) {
                const int c = status[i];
                if (c == 1) {
                    bit1 |= 1 << i;
                } else if (c == 2) {
                    bit2 |= 1 << i;
                } else {
                    if (dp[i][nextBits(i)]) {
                        bit3 |= 1 << i;
                    } else {
                        bit4 |= 1 << i;
                    }
                }
            }
            for (int f = 0; f < n; ++f) {
                if (status[f] == 0) {
                    continue;
                }
                if (a[f] == 1) {
                    bool isOk = false;
                    isOk |= (bit2 && graphBit[f]);
                    isOk |= (bit3 && graphBit[f]);
                    dp[f][bits] = isOk;
                } else {
                    bool isOk = true;
                    if (bit1 && graphBit[f]) {
                        isOk = false;
                    } else if (bit4 && graphBit[f]) {
                        isOk = false;
                    }
                    dp[f][bits] = isOk;
                }
            }
        }
        
        std::vector<int> answer(n);
        for (int i = 0; i < n; ++i) {
            answer[i] = dp[i][pow3[i] * (r[i] + 1)] ? 1 : 0;
        }
        return answer;
    } else {
        // subtask 1
        std::vector<int> answer(n);
        for (int i = 0; i < n; ++i) {
            int now = i;
            while (true) {
                if (a[now] == 1) {
                    if (r[now] == 1 and std::find(graph[now].begin(), graph[now].end(), now) != graph[now].end()) {
                        answer[i] = 1;
                        break;
                    }
                    if (graph[now].size() == 1 and graph[now][0] == now) {
                        answer[i] = 0;
                        break;
                    }
                    ++now;
                } else {
                    if (r[now] == 0 and std::find(graph[now].begin(), graph[now].end(), now) != graph[now].end()) {
                        answer[i] = 0;
                        break;
                    }
                    if (graph[now].size() == 1 and graph[now][0] == now) {
                        answer[i] = 1;
                        break;
                    }
                    ++now;
                }
            }
        }
        return answer;
    }
}

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