Your task is to write a function that, given a distance d and a stream of floating-point values received one at a time, checks for groups of three values that are within at most d distance.
As values are received, they should be stored in memory.
Whenever any group is found meeting the distance criteria, return the three values and remove them from memory.
这道题考察的是流式数据处理和区间匹配：输入是一个不断到来的浮点数序列，需要在内存中维护已接收的值，并尽快找出任意三个数，使得它们之间的距离满足题目要求。常见思路是先将数据按数值有序维护，或在滑动窗口 / 平衡搜索结构中持续查询当前值附近是否能组成合法三元组；一旦找到，就立刻返回这三个值并从存储中删除。核心在于高效地支持“插入、查找邻近值、删除”这三类操作。
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