在很长的列表中查找重复项时，Python会崩溃

def find_duplicates(lst):
    duplicates = []
    for i in range(len(lst)):
        for j in range(i+1, len(lst)):
            if lst[i] == lst[j] and lst[i] not in duplicates:
                duplicates.append(lst[i])
    return duplicates

# 示例用法
my_list = [1, 2, 3, 4, 5, 2, 3, 6]
result = find_duplicates(my_list)
print(result)  # 输出 [2, 3]

def find_duplicates(lst):
    duplicates = []
    if len(lst) != len(set(lst)):
        duplicates = list(set([x for x in lst if lst.count(x) > 1]))
    return duplicates

# 示例用法
my_list = [1, 2, 3, 4, 5, 2, 3, 6]
result = find_duplicates(my_list)
print(result)  # 输出 [2, 3]

from collections import Counter

def find_duplicates(lst):
    duplicates = [item for item, count in Counter(lst).items() if count > 1]
    return duplicates

# 示例用法
my_list = [1, 2, 3, 4, 5, 2, 3, 6]
result = find_duplicates(my_list)
print(result)  # 输出 [2, 3]