Unordered Subsequence

题意翻译

【题面描述】 如果一个序列是递增或递降的（相等也算增或降），则称它为有序的。给定一个序列，找出最短的非有序的子序列。子序列可以不连续。 【输入格式】 第1行，序列长度N。 第2行，N个数的序列。 【输出格式】 第1行，最短长度K。 第2行，K个数，表示最短非有序子序列中，每个数在原序列中的下标。 感谢@刷题永动机 提供的翻译

题目描述

The sequence is called ordered if it is non-decreasing or non-increasing. For example, sequnces \[3, 1, 1, 0\] and \[1, 2, 3, 100\] are ordered, but the sequence \[1, 3, 3, 1\] is not. You are given a sequence of numbers. You are to find it's shortest subsequence which is not ordered. A subsequence is a sequence that can be derived from the given sequence by deleting zero or more elements without changing the order of the remaining elements.

输入输出格式

输入格式

The first line of the input contains one integer $ n $ ( $ 1<=n<=10^{5} $ ). The second line contains $ n $ space-separated integers — the given sequence. All numbers in this sequence do not exceed $ 10^{6} $ by absolute value.

输出格式

If the given sequence does not contain any unordered subsequences, output $ 0 $ . Otherwise, output the length $ k $ of the shortest such subsequence. Then output $ k $ integers from the range \[1.. $ n $ \] — indexes of the elements of this subsequence. If there are several solutions, output any of them.

输入输出样例

输入样例 #1

5
67 499 600 42 23

输出样例 #1

3
1 3 5

输入样例 #2

3
1 2 3

输出样例 #2

0

输入样例 #3

3
2 3 1

输出样例 #3

3
1 2 3