- Difficulty: Hard
- Tags: LeetCode, Hard, Math, Enumeration, leetcode-906, O(n^0.25 * logn), O(logn)
Problem
Let's say a positive integer is a super-palindrome if it is a palindrome, and it is also the square of a palindrome.
Given two positive integers left
and right
represented as strings, return the number of super-palindromes integers in the inclusive range [left, right]
.
Example 1:
Input: left = "4", right = "1000" Output: 4 Explanation: 4, 9, 121, and 484 are superpalindromes. Note that 676 is not a superpalindrome: 26 * 26 = 676, but 26 is not a palindrome.
Example 2:
Input: left = "1", right = "2" Output: 1
Constraints:
1 <= left.length, right.length <= 18
left
andright
consist of only digits.left
andright
cannot have leading zeros.left
andright
represent integers in the range[1, 1018 - 1]
.left
is less than or equal toright
.