提出 #43863584

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ソースコード 拡げる

#!/usr/bin/env python3
from typing import *


def solve(N: int, A: List[int]) -> Tuple[int, List[int]]:
    adjacency_list = [[] for _ in range(N+1)]
    for a_index in range(1, N+1):
        adjacency_list[a_index] = A[a_index-1]

    result_m = 0
    result_b = []
    for node_index in range(1, N+1):
        node_num = 2
        position = adjacency_list[node_index]
        path = [node_index, position]

        while True:
            if node_num > N:
                break

            if position == node_index:
                result_m = node_num
                result_b = path
                return result_m, result_b

            position = adjacency_list[position]
            if position != node_index:
                node_num += 1
                path.append(position)

    return result_m, result_b


def solve_speedy(N: int, A: List[int]) -> Tuple[int, List[int]]:
    current_path = [0 for _ in range(N+1)]
    current_path[1] = A[0]
    position = A[0]
    while current_path[position] == 0:
        current_path[position] = A[position-1]
        position = A[position-1]

    circle_start_position = position
    result_m = 0
    result_b = []
    while True:
        result_m += 1
        result_b.append(position)
        position = A[position-1]
        if position == circle_start_position:
            break

    return result_m, result_b


# generated by oj-template v4.8.1 (https://github.com/online-judge-tools/template-generator)
def main():
    N = int(input())
    A = list(map(int, input().split(' ')))
    M, B = solve_speedy(N, A)
    print(M)
    print(*[B[i] for i in range(M)])


if __name__ == '__main__':
    main()

提出情報

ジャッジ結果