"""# ### 谜题描述 Patrick likes to play baseball, but sometimes he will spend so many hours hitting home runs that his mind starts to get foggy! Patrick is sure that his scores across n sessions follow the identity permutation (ie. in the first game he scores 1 point, in the second game he scores 2 points and so on). However, when he checks back to his record, he sees that all the numbers are mixed up! Define a special exchange as the following: choose any subarray of the scores and permute elements such that no element of subarray gets to the same position as it was before the exchange. For example, performing a special exchange on [1,2,3] can yield [3,1,2] but it cannot yield [3,2,1] since the 2 is in the same position. Given a permutation of n integers, please help Patrick find the minimum number of special exchanges needed to make the permutation sorted! It can be proved that under given constraints this number doesn't exceed 10^{18}. An array a is a subarray of an array b if a can be obtained from b by deletion of several (possibly, zero or all) elements from the beginning and several (possibly, zero or all) elements from the end. Input Each test contains multiple test cases. The first line contains the number of test cases t (1 ≤ t ≤ 100). Description of the test cases follows. The first line of each test case contains integer n (1 ≤ n ≤ 2 ⋅ 10^5) — the length of the given permutation. The second line of each test case contains n integers a_{1},a_{2},...,a_{n} (1 ≤ a_{i} ≤ n) — the initial permutation. It is guaranteed that the sum of n over all test cases does not exceed 2 ⋅ 10^5. Output For each test case, output one integer: the minimum number of special exchanges needed to sort the permutation. Example Input 2 5 1 2 3 4 5 7 3 2 4 5 1 6 7 Output 0 2 Note In the first permutation, it is already sorted so no exchanges are needed. It can be shown that you need at least 2 exchanges to sort the second permutation. [3, 2, 4, 5, 1, 6, 7] Perform special exchange on range (1, 5) [4, 1, 2, 3, 5, 6, 7] Perform special exchange on range (1, 4) [1, 2, 3, 4, 5, 6, 7] Here is a reference code to solve this task. You can use this to help you genereate cases or validate the solution. ```python from __future__ import division, print_function import os import sys from io import BytesIO, IOBase if sys.version_info[0] < 3: from __builtin__ import xrange as range from future_builtins import ascii, filter, hex, map, oct, zip # ------------------------------ TEMPLATE ABOVE THIS -------------------------------- def main(): t=int(input()) for _ in range(t): n=int(input()) A=list(map(int,input().split())) B=A[:] B.sort() cnt=0 i=0 while i= 2: arr[start2:end2+1] = sub2[1:] + sub2[:1] if self._compute_answer(arr) == 2: answer = 2 break return { 'n': n, 'arr': arr, 'answer': answer } @staticmethod def _compute_answer(a): """根据官方参考代码实现的答案验证逻辑""" B = sorted(a) cnt = 0 i, n = 0, len(a) while i < n: while i < n and a[i] == B[i]: i += 1 flag = 0 while i < n and a[i] != B[i]: i += 1 flag = 1 if flag: cnt += 1 return cnt if cnt <= 1 else 2 @staticmethod def prompt_func(question_case): return f"""Patrick needs to sort his baseball score records using special exchanges. Given the permutation: n = {question_case['n']} {question_case['arr']} Calculate the minimum number of special exchanges required. Put your final answer within [answer] and [/answer] tags. For example: [answer]2[/answer]""" @staticmethod def extract_output(output): # 逆向搜索最后一个答案标签对 end_pos = output.rfind('[/answer]') if end_pos == -1: return None start_pos = output.rfind('[answer]', 0, end_pos) if start_pos == -1: return None return output[start_pos+8:end_pos].strip() @classmethod def _verify_correction(cls, solution, identity): try: return int(solution) == identity['answer'] except (ValueError, KeyError): return False