結果

問題 No.5022 XOR Printer
ユーザー prussian_coder
提出日時 2025-07-15 10:46:12
言語 C++23
(gcc 13.3.0 + boost 1.87.0)
結果
MLE  
実行時間 -
コード長 6,686 bytes
コンパイル時間 2,385 ms
コンパイル使用メモリ 170,620 KB
実行使用メモリ 814,464 KB
スコア 0
最終ジャッジ日時 2025-07-26 12:40:15
合計ジャッジ時間 7,238 ms
ジャッジサーバーID
(参考情報)
judge5 / judge1
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
other MLE * 1 -- * 49
権限があれば一括ダウンロードができます

ソースコード

diff #

#pragma GCC optimize "-O3,omit-frame-pointer,inline,unroll-all-loops,fast-math"

#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>      // for accumulate
#include <unordered_set>
#include <cstdint>
#include <utility>
#include <limits>
#include <functional>

using namespace std;

static int N, T;
static int N2;
static vector<vector<int>> NEAR_POS;

inline pair<int,int> to2d(int p) {
    return {p / N, p % N};
}
inline int manhattan_distance(int p1, int p2) {
    auto [x1,y1] = to2d(p1);
    auto [x2,y2] = to2d(p2);
    return abs(x1 - x2) + abs(y1 - y2);
}

vector<char> generate_move_commands(int start, int end) {
    vector<char> cmds;
    auto [x1,y1] = to2d(start);
    auto [x2,y2] = to2d(end);
    int cx = x1, cy = y1;
    while (cx < x2) { cmds.push_back('D'); ++cx; }
    while (cx > x2) { cmds.push_back('U'); --cx; }
    while (cy < y2) { cmds.push_back('R'); ++cy; }
    while (cy > y2) { cmds.push_back('L'); --cy; }
    return cmds;
}

struct State {
    vector<int> board;
    int s, pos, turn, score, prev_c_cnt;
    State* prev_state;
    pair<char,int> prev_action;
    State(const vector<int>& b, int _s, int _pos, int _turn, int _score)
        : board(b), s(_s), pos(_pos), turn(_turn), score(_score), prev_c_cnt(0), prev_state(nullptr), prev_action({'?',0}) {}
};

bool state_is_valid(const State* st) {
    if (st->turn == T) return true;
    int mask = (1 << 19) - 1;
    for (int v : st->board) {
        mask &= v;
        if (mask == 0) return true;
    }
    return false;
}

int state_last_score(const State* st) {
    int min_v = numeric_limits<int>::max();
    int min_pos = 0;
    for (int i = 0; i < N2; ++i) {
        if (st->board[i] < min_v) {
            min_v = st->board[i];
            min_pos = i;
        }
    }
    int dist = manhattan_distance(st->pos, min_pos);
    if (st->turn + dist + 3 >= T) return 0;
    return st->score + st->s - min_v;
}

vector<char> state_last_move(const State* st) {
    int min_v = numeric_limits<int>::max();
    int min_pos = 0;
    for (int i = 0; i < N2; ++i) {
        if (st->board[i] < min_v) {
            min_v = st->board[i];
            min_pos = i;
        }
    }
    auto cmds = generate_move_commands(st->pos, min_pos);
    cmds.push_back('W');
    cmds.push_back('C');
    cmds.push_back('W');
    return cmds;
}

struct BeamSearchSolver {
    const int beam_width = 300;
    const int state_que_size = 10;
    struct PairHash { size_t operator()(uint64_t x) const { return x; } };

    State* process(const vector<int>& init_board) {
        vector<vector<State*>> states(state_que_size);
        auto cmp = [](State* a, State* b) { return a->score > b->score; };

        State* initial = new State(init_board, 0, 0, 0,
            accumulate(init_board.begin(), init_board.end(), 0));
        states[0].push_back(initial);
        push_heap(states[0].begin(), states[0].end(), cmp);

        int best_score = 0;
        State* best_state = nullptr;

        for (int turn = 0; turn < T; ++turn) {
            int idx = turn % state_que_size;
            auto curr = states[idx];
            states[idx].clear();

            unordered_set<uint64_t, PairHash> seen;
            for (State* st : curr) {
                uint64_t key = (uint64_t(st->score) << 32) | uint32_t(st->s);
                if (seen.count(key)) continue;
                seen.insert(key);
                for (int v2 : NEAR_POS[st->pos]) {
                    try_push(st, 'W', v2, states, cmp);
                    if (st->prev_c_cnt < 2) try_push(st, 'C', v2, states, cmp);
                }
            }
            for (State* st : curr) {
                int fs = state_last_score(st);
                if (fs > best_score) {
                    best_score = fs;
                    best_state = st;
                }
            }
        }
        return best_state;
    }

    void try_push(State* st, char key, int pos,
                  vector<vector<State*>>& states,
                  const function<bool(State*,State*)>& cmp) {
        int dist = manhattan_distance(st->pos, pos);
        int next_turn = st->turn + dist + 1;
        if (next_turn > T) return;
        int new_score = (key == 'C' ? st->score
                          : st->score + ((st->board[pos] ^ st->s) - st->board[pos]));
        int idx = next_turn % state_que_size;
        auto& q = states[idx];
        if ((int)q.size() < beam_width) {
            State* ns = apply_move(st, key, pos, next_turn, new_score);
            if (state_is_valid(ns)) {
                q.push_back(ns);
                push_heap(q.begin(), q.end(), cmp);
            }
        } else if (new_score > q.front()->score) {
            State* ns = apply_move(st, key, pos, next_turn, new_score);
            if (state_is_valid(ns)) {
                pop_heap(q.begin(), q.end(), cmp);
                q.pop_back();
                q.push_back(ns);
                push_heap(q.begin(), q.end(), cmp);
            }
        }
    }

    State* apply_move(State* st, char key, int pos, int next_turn, int new_score) {
        State* ns = new State(*st);
        ns->prev_state = st;
        ns->prev_action = {key, st->pos};
        ns->turn = next_turn;
        ns->score = new_score;
        if (key == 'C') {
            ns->s ^= st->board[pos];
            ns->prev_c_cnt = st->prev_c_cnt + 1;
        } else {
            ns->board[pos] = st->board[pos] ^ st->s;
            ns->prev_c_cnt = 0;
        }
        ns->pos = pos;
        return ns;
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> T;
    N2 = N * N;
    vector<int> board;
    board.reserve(N2);
    for (int i = 0; i < N2; ++i) {
        int x; cin >> x;
        board.push_back(x);
    }
    NEAR_POS.assign(N2, {});
    for (int i = 0; i < N2; ++i) {
        for (int j = 0; j < N2; ++j) {
            if (manhattan_distance(i, j) <= 8) {
                NEAR_POS[i].push_back(j);
            }
        }
    }

    BeamSearchSolver solver;
    State* best = solver.process(board);
    vector<char> last_actions = state_last_move(best);
    vector<char> actions;
    for (State* cur = best; cur->prev_state != nullptr; cur = cur->prev_state) {
        auto [key, last_pos] = cur->prev_action;
        actions.push_back(key);
        auto cmds = generate_move_commands(last_pos, cur->pos);
        for (auto it = cmds.rbegin(); it != cmds.rend(); ++it) {
            actions.push_back(*it);
        }
    }
    reverse(actions.begin(), actions.end());
    actions.insert(actions.end(), last_actions.begin(), last_actions.end());
    for (char c : actions) {
        cout << c << '\n';
    }

    return 0;
}
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