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