从列表中查找最长的唯一条目

def find_longest_unique_item(lst):
    unique_items = set()
    longest_length = 0
    longest_item = None

    for item in lst:
        if item in unique_items:
            continue

        unique_items.add(item)
        if len(item) > longest_length:
            longest_length = len(item)

    for item in lst:
        if len(item) == longest_length and item not in unique_items:
            longest_item = item
            break

    return longest_item

# 示例用法
my_list = ["apple", "banana", "orange", "apple", "grape", "banana"]
result = find_longest_unique_item(my_list)
print(result)  # 输出: "orange"