- Difficulty: Medium
- Tags: LeetCode, Medium, Math, Number Theory, leetcode-2523, O(MAXN), Linear Sieve of Eratosthenes, Segment Tree
Problem
Given two positive integers left
and right
, find the two integers num1
and num2
such that:
left <= num1 < num2 <= right
.num1
andnum2
are both prime numbers.num2 - num1
is the minimum amongst all other pairs satisfying the above conditions.
Return the positive integer array ans = [num1, num2]
. If there are multiple pairs satisfying these conditions, return the one with the minimum num1
value or [-1, -1]
if such numbers do not exist.
A number greater than 1
is called prime if it is only divisible by 1
and itself.
Example 1:
Input: left = 10, right = 19 Output: [11,13] Explanation: The prime numbers between 10 and 19 are 11, 13, 17, and 19. The closest gap between any pair is 2, which can be achieved by [11,13] or [17,19]. Since 11 is smaller than 17, we return the first pair.
Example 2:
Input: left = 4, right = 6 Output: [-1,-1] Explanation: There exists only one prime number in the given range, so the conditions cannot be satisfied.
Constraints:
1 <= left <= right <= 106