Submission #20133410

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Source Code Expand

import sys
import numpy as np

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

def from_read(dtype=np.int64):
    return np.fromstring(read().decode(), dtype=dtype, sep=' ')


def from_readline(dtype=np.int64):
    return np.fromstring(readline().decode(), dtype=dtype, sep=' ')


def output(ANS):
    print(len(ANS))
    for i in ANS:
        print(i + 1)

def check(A, ANS):
    A = A.copy()
    for i in ANS:
        A[:i] = A[:i][::-1]
        A[i + 1:] = A[i + 1:][::-1]
    for i in range(len(A)):
        assert A[i] == i

def attempt(A, t):
    N = len(A)
    A = A.copy()
    ANS = []

    def ope(i):
        ANS.append(i)
        A[:i] = A[:i][::-1]
        A[i + 1:] = A[i + 1:][::-1]

    for _ in range(9900 - 2 * N - t):
        i = np.random.randint(0, N)
        ope(i)

    i = np.where(A == 0)[0][0]
    if i != N - 1:
        ope(i + 1)
        L, R = 1, 0
    else:
        L, R = 0, 1

    while L < N and R < N:
        if L > 0:
            # 左に、L-1, ..., 1, 0 というのができている
            k = np.where(A == L)[0][0]
            if k < N - 1:
                ope(k)
                ope(k + 1)
                L += 1
            else:
                ope(k)
                L, R = 0, L + 1
        elif R > 0:
            # 右に、0,1,...,R-1 というのができている
            k = np.where(A == R)[0][0]
            if k > 0:
                ope(k)
                ope(k - 1)
                R += 1
            else:
                ope(0)
                L, R = R + 1, 0
    if R == N:
        return True, ANS
    else:
        return False, ANS

def main(A):
    N = len(A)
    A = A - 1
    for t in range(10):
        ok, ANS = attempt(A, t)
        if ok:
            check(A, ANS)
            output(ANS)
            return
    print(-1)

A = from_read()[1:]

main(A)

Submission Info

Judge Result