为列表中的相似值返回相同的位置

def find_similar_positions(lst, threshold):
    similar_positions = {}

    for i in range(len(lst)):
        for j in range(i+1, len(lst)):
            if abs(lst[i] - lst[j]) <= threshold:
                if lst[i] in similar_positions:
                    similar_positions[lst[i]].append(i)
                else:
                    similar_positions[lst[i]] = [i]
                
                if lst[j] in similar_positions:
                    similar_positions[lst[j]].append(j)
                else:
                    similar_positions[lst[j]] = [j]

    return similar_positions

# 示例输入
input_list = [1, 2, 3, 5, 6, 8, 9, 11, 12]
threshold = 2

# 调用函数并输出结果
similar_positions = find_similar_positions(input_list, threshold)
print(similar_positions)