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187 lines
5.3 KiB
Python
Executable file
187 lines
5.3 KiB
Python
Executable file
"""#
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### 谜题描述
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You are given a permutation p of length n. Remove one element from permutation to make the number of records the maximum possible.
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We remind that in a sequence of numbers a1, a2, ..., ak the element ai is a record if for every integer j (1 ≤ j < i) the following holds: aj < ai.
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Input
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The first line contains the only integer n (1 ≤ n ≤ 105) — the length of the permutation.
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The second line contains n integers p1, p2, ..., pn (1 ≤ pi ≤ n) — the permutation. All the integers are distinct.
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Output
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Print the only integer — the element that should be removed to make the number of records the maximum possible. If there are multiple such elements, print the smallest one.
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Examples
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Input
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1
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1
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Output
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1
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Input
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5
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5 1 2 3 4
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Output
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5
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Note
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In the first example the only element can be removed.
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Here is a reference code to solve this task. You can use this to help you genereate cases or validate the solution.
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```python
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import bisect
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n = int(raw_input())
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p = map(int, raw_input().split())
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# nums_sorted = [p[0]]
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nums_sorted = []
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record_prevented = [0 for i in range(n+1)]
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# record_prevented[p[0]] = -1
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for num in p:
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bisect.insort(nums_sorted, num)
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ind = nums_sorted.index(num)
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if ind == len(nums_sorted) - 1:
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record_prevented[num] = -1
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elif ind == len(nums_sorted) - 2:
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record_prevented[nums_sorted[-1]] += 1
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if len(nums_sorted) > 2:
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nums_sorted.pop(0)
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mx, mx_num = -1, 1
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for num, rec_prev in enumerate(record_prevented):
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if rec_prev > mx and num > 0:
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mx = rec_prev
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mx_num = num
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print mx_num
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```
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请完成上述谜题的训练场环境类实现,包括所有必要的方法。
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"""
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from bootcamp import Basebootcamp
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import random
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import re
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import bisect
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from bootcamp import Basebootcamp
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class Cremoveextraonebootcamp(Basebootcamp):
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def __init__(self, min_n=1, max_n=10):
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"""
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Initialize permutation record puzzle bootcamp with parameters for permutation size.
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Args:
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min_n (int): Minimum length of permutation (inclusive)
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max_n (int): Maximum length of permutation (inclusive)
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"""
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self.min_n = min_n
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self.max_n = max_n
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def case_generator(self):
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"""
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Generate a permutation puzzle case with optimal removable element.
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Returns:
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dict: {'n', 'p', 'answer'} where p is permutation list, answer is optimal element
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"""
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n = random.randint(self.min_n, self.max_n)
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p = list(range(1, n+1))
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random.shuffle(p)
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answer = self._compute_correct_answer(p)
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return {
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'n': n,
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'p': p,
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'answer': answer
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}
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@staticmethod
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def _compute_correct_answer(p):
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"""
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Compute correct answer using optimized approach from reference code.
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"""
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n = len(p)
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nums_sorted = []
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record_prevented = [0] * (n + 2) # +2 to avoid index issues
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for num in p:
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bisect.insort(nums_sorted, num)
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ind = nums_sorted.index(num)
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if ind == len(nums_sorted) - 1:
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record_prevented[num] = -1
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elif ind == len(nums_sorted) - 2:
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record_prevented[nums_sorted[-1]] += 1
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if len(nums_sorted) > 2:
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nums_sorted.pop(0)
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mx, mx_num = -1, float('inf')
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for num in range(1, n+1):
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if record_prevented[num] > mx or (record_prevented[num] == mx and num < mx_num):
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mx = record_prevented[num]
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mx_num = num
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return mx_num
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@staticmethod
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def prompt_func(question_case) -> str:
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"""
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Format the puzzle case into an instructional prompt with answer format specification.
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"""
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n = question_case['n']
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p_str = ' '.join(map(str, question_case['p']))
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return f"""You are participating in a programming competition. Solve the following problem:
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**Problem Statement:**
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Given a permutation p of length n, remove exactly one element to maximize the number of records in the remaining sequence. A record is an element that is larger than all preceding elements. If multiple elements yield the maximum records, choose the smallest one.
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**Input Format:**
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- First line: Integer n ({n} in this case)
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- Second line: Space-separated permutation elements ({p_str})
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**Output Format:**
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A single integer - the element to remove. Place your answer between [answer] and [/answer] tags.
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**Example:**
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For input:
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5
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5 1 2 3 4
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The correct answer is [answer]5[/answer].
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**Your Task:**
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Apply the problem-solving process and output your final answer within the specified tags."""
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@staticmethod
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def extract_output(output):
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"""
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Extract the last occurrence of an answer between [answer] tags.
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"""
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matches = re.findall(r'\[answer\](.*?)\[/answer\]', output, re.DOTALL)
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if not matches:
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return None
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try:
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return int(matches[-1].strip())
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except (ValueError, TypeError):
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return None
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@classmethod
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def _verify_correction(cls, solution, identity):
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"""
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Verify if extracted solution matches precomputed answer.
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"""
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return solution == identity['answer']
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