Problem Brief
Smallest Set Covering Intervals
INTERNOA
Given a series of integer intervals, determine the size of the smallest set that contains at least 2 integers within each interval.
Function Description
Complete the function interval in the editor.
interval has the following parameters:
- 1.
int first[n]: each element represents the start of intervali - 2.
int last[n]: each element represents the end of intervali
Returns
int: the size of the smallest interval possible
1Example 1
Input
first = [0, 1, 2], last = [2, 3, 3]
Output
3
Explanation

The intervals start at first[i] and end at last[i].
Both intervals 0 and 1 contain 1 and 2. These are the only two integers that interval 0 shares, so both integers must be included in the answer set. Both intervals 1 and 2 contain 2 and 3. These are the only two values that interval 2 shares. The smallest set that contains at least 2 integers from each interval is {1, 2, 3}.
Constraints
Limits and guarantees your solution can rely on.
- 1 ≤ n ≤ 105
- 0 ≤
first[i]≤last[i]≤ 109