InternBootcamp/internbootcamp/bootcamp/cremoveextraone/cremoveextraone.py
2025-05-23 15:27:15 +08:00

187 lines
5.3 KiB
Python
Executable file

"""#
### 谜题描述
You are given a permutation p of length n. Remove one element from permutation to make the number of records the maximum possible.
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.
Input
The first line contains the only integer n (1 ≤ n ≤ 105) — the length of the permutation.
The second line contains n integers p1, p2, ..., pn (1 ≤ pi ≤ n) — the permutation. All the integers are distinct.
Output
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.
Examples
Input
1
1
Output
1
Input
5
5 1 2 3 4
Output
5
Note
In the first example the only element can be removed.
Here is a reference code to solve this task. You can use this to help you genereate cases or validate the solution.
```python
import bisect
n = int(raw_input())
p = map(int, raw_input().split())
# nums_sorted = [p[0]]
nums_sorted = []
record_prevented = [0 for i in range(n+1)]
# record_prevented[p[0]] = -1
for num in p:
bisect.insort(nums_sorted, num)
ind = nums_sorted.index(num)
if ind == len(nums_sorted) - 1:
record_prevented[num] = -1
elif ind == len(nums_sorted) - 2:
record_prevented[nums_sorted[-1]] += 1
if len(nums_sorted) > 2:
nums_sorted.pop(0)
mx, mx_num = -1, 1
for num, rec_prev in enumerate(record_prevented):
if rec_prev > mx and num > 0:
mx = rec_prev
mx_num = num
print mx_num
```
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。
"""
from bootcamp import Basebootcamp
import random
import re
import bisect
from bootcamp import Basebootcamp
class Cremoveextraonebootcamp(Basebootcamp):
def __init__(self, min_n=1, max_n=10):
"""
Initialize permutation record puzzle bootcamp with parameters for permutation size.
Args:
min_n (int): Minimum length of permutation (inclusive)
max_n (int): Maximum length of permutation (inclusive)
"""
self.min_n = min_n
self.max_n = max_n
def case_generator(self):
"""
Generate a permutation puzzle case with optimal removable element.
Returns:
dict: {'n', 'p', 'answer'} where p is permutation list, answer is optimal element
"""
n = random.randint(self.min_n, self.max_n)
p = list(range(1, n+1))
random.shuffle(p)
answer = self._compute_correct_answer(p)
return {
'n': n,
'p': p,
'answer': answer
}
@staticmethod
def _compute_correct_answer(p):
"""
Compute correct answer using optimized approach from reference code.
"""
n = len(p)
nums_sorted = []
record_prevented = [0] * (n + 2) # +2 to avoid index issues
for num in p:
bisect.insort(nums_sorted, num)
ind = nums_sorted.index(num)
if ind == len(nums_sorted) - 1:
record_prevented[num] = -1
elif ind == len(nums_sorted) - 2:
record_prevented[nums_sorted[-1]] += 1
if len(nums_sorted) > 2:
nums_sorted.pop(0)
mx, mx_num = -1, float('inf')
for num in range(1, n+1):
if record_prevented[num] > mx or (record_prevented[num] == mx and num < mx_num):
mx = record_prevented[num]
mx_num = num
return mx_num
@staticmethod
def prompt_func(question_case) -> str:
"""
Format the puzzle case into an instructional prompt with answer format specification.
"""
n = question_case['n']
p_str = ' '.join(map(str, question_case['p']))
return f"""You are participating in a programming competition. Solve the following problem:
**Problem Statement:**
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.
**Input Format:**
- First line: Integer n ({n} in this case)
- Second line: Space-separated permutation elements ({p_str})
**Output Format:**
A single integer - the element to remove. Place your answer between [answer] and [/answer] tags.
**Example:**
For input:
5
5 1 2 3 4
The correct answer is [answer]5[/answer].
**Your Task:**
Apply the problem-solving process and output your final answer within the specified tags."""
@staticmethod
def extract_output(output):
"""
Extract the last occurrence of an answer between [answer] tags.
"""
matches = re.findall(r'\[answer\](.*?)\[/answer\]', output, re.DOTALL)
if not matches:
return None
try:
return int(matches[-1].strip())
except (ValueError, TypeError):
return None
@classmethod
def _verify_correction(cls, solution, identity):
"""
Verify if extracted solution matches precomputed answer.
"""
return solution == identity['answer']