結果

問題 No.813 ユキちゃんの冒険
ユーザー lam6er
提出日時 2025-04-09 21:02:54
言語 PyPy3
(7.3.15)
結果
TLE  
実行時間 -
コード長 1,650 bytes
コンパイル時間 249 ms
コンパイル使用メモリ 82,732 KB
実行使用メモリ 89,672 KB
最終ジャッジ日時 2025-04-09 21:04:51
合計ジャッジ時間 5,619 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge2
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 AC * 25 TLE * 1
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 # 

def main():
    import sys
    input_lines = sys.stdin.read().splitlines()
    N = int(input_lines[0])
    p = float(input_lines[1])
    q = float(input_lines[2])

    max_iterations = 1000000
    epsilon = 1e-12

    # Initialize previous arrays
    prev_r = [0.0] * (N + 2)  # indexes 0..N+1, using 1..N
    prev_l = [0.0] * (N + 2)
    prev_r[1] = 1.0  # initial state: gate 1, right direction

    for _ in range(max_iterations):
        curr_r = [0.0] * (N + 2)
        curr_l = [0.0] * (N + 2)
        max_diff = 0.0

        # Update current arrays
        for i in range(1, N + 1):
            # Handle curr_r[i]
            curr_r[i] = 0.0
            if i == 1:
                curr_r[i] += 1.0  # initial condition
            if i > 1:
                curr_r[i] += q * prev_r[i-1]  # from i-1, right (pass)
                curr_r[i] += p * prev_l[i-1]  # from i-1, left (flee)
            
            # Handle curr_l[i]
            curr_l[i] = 0.0
            if i < N:
                curr_l[i] += q * prev_l[i+1]  # from i+1, left (pass)
                curr_l[i] += p * prev_r[i+1]  # from i+1, right (flee)

        # Compute max difference
        for i in range(1, N+1):
            max_diff = max(max_diff, abs(curr_r[i] - prev_r[i]), abs(curr_l[i] - prev_l[i]))
        
        # Check convergence
        if max_diff < epsilon:
            break

        # Swap current to previous for next iteration
        prev_r, curr_r = curr_r, prev_r
        prev_l, curr_l = curr_l, prev_l

    # Calculate the result
    result = p * prev_r[1] + q * prev_l[1]
    print("{0:.15f}".format(result))

if __name__ == "__main__":
    main()
0