結果

問題 No.1284 Flip Game
コンテスト
ユーザー lam6er
提出日時 2025-04-16 01:12:22
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 1,144 ms / 2,000 ms
コード長 2,350 bytes
コンパイル時間 399 ms
コンパイル使用メモリ 81,240 KB
実行使用メモリ 131,040 KB
最終ジャッジ日時 2025-04-16 01:14:08
合計ジャッジ時間 8,997 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 28
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 # 

import heapq

def main():
    N = int(input())
    c = [list(map(int, input().split())) for _ in range(N)]
    INF = float('inf')
    full_mask = (1 << N) - 1

    heap = []
    dist = dict()

    for q0 in range(N):
        initial_mask = 1 << q0
        prev = q0
        flipped_B = 0
        state = (initial_mask, prev, flipped_B)
        if state not in dist or 0 < dist.get(state, INF):
            dist[state] = 0
            heapq.heappush(heap, (0, initial_mask, prev, flipped_B))

    answer = INF

    while heap:
        current_cost, mask, prev, flipped_B = heapq.heappop(heap)

        if current_cost > dist.get((mask, prev, flipped_B), INF):
            continue

        for next_q in range(N):
            if not (mask & (1 << next_q)):
                cost_step = c[prev][next_q]
                new_mask_A = mask | (1 << next_q)

                if new_mask_A == full_mask:
                    if (flipped_B & (1 << prev)):
                        if current_cost + cost_step < answer:
                            answer = current_cost + cost_step
                        continue
                    else:
                        new_mask = new_mask_A ^ (1 << prev)
                        new_flipped_B = flipped_B | (1 << prev)
                        new_prev = next_q
                        new_cost = current_cost + cost_step
                        key = (new_mask, new_prev, new_flipped_B)
                        if new_cost < dist.get(key, INF):
                            dist[key] = new_cost
                            heapq.heappush(heap, (new_cost, new_mask, new_prev, new_flipped_B))
                else:
                    if (flipped_B & (1 << prev)) == 0:
                        new_mask = new_mask_A ^ (1 << prev)
                        new_flipped_B = flipped_B | (1 << prev)
                    else:
                        new_mask = new_mask_A
                        new_flipped_B = flipped_B
                    new_prev = next_q
                    new_cost = current_cost + cost_step
                    key = (new_mask, new_prev, new_flipped_B)
                    if new_cost < dist.get(key, INF):
                        dist[key] = new_cost
                        heapq.heappush(heap, (new_cost, new_mask, new_prev, new_flipped_B))

    print(answer)

if __name__ == "__main__":
    main()
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