> For the complete documentation index, see [llms.txt](https://jaywin.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jaywin.gitbook.io/leetcode/solutions/0757-set-intersection-size-at-least-two.md).

# 0757. Set Intersection Size At Least Two

<https://leetcode.com/problems/set-intersection-size-at-least-two>

## Description

An integer interval `[a, b]` (for integers `a < b`) is a set of all consecutive integers from `a` to `b`, including `a` and `b`.

Find the minimum size of a set S such that for every integer interval A in `intervals`, the intersection of S with A has a size of at least two.

**Example 1:**

```
**Input:** intervals = [[1,3],[1,4],[2,5],[3,5]]
**Output:** 3
**Explanation:** Consider the set S = {2, 3, 4}.  For each interval, there are at least 2 elements from S in the interval.
Also, there isn't a smaller size set that fulfills the above condition.
Thus, we output the size of this set, which is 3.
```

**Example 2:**

```
**Input:** intervals = [[1,2],[2,3],[2,4],[4,5]]
**Output:** 5
**Explanation:** An example of a minimum sized set is {1, 2, 3, 4, 5}.
```

**Constraints:**

* `1 <= intervals.length <= 3000`
* `intervals[i].length == 2`
* `0 <= ai < bi <= 108`

## ac

```java
```