Is Largest Palindrome Product easy or hard?

Largest Palindrome Product is rated Hard on LeetCode because the straightforward brute force approach is too slow for larger inputs. The challenge lies in recognizing the symmetry of palindromes and generating them efficiently before checking valid factors.

Largest Palindrome Product Python/Java solution

Python and Java implementations usually follow the palindrome-construction approach: generate a mirrored palindrome from a prefix, then check divisibility by n-digit numbers. The first valid palindrome found is returned modulo 1337 as required by the problem.

How to solve Largest Palindrome Product in O(n)?

A strict O(n) solution does not exist because the algorithm must explore multiple candidate palindromes and divisors. The practical optimization is generating palindromes first and checking divisibility by n-digit numbers, which reduces the effective complexity to roughly O(10^n) rather than enumerating every product.

What is the best approach for Largest Palindrome Product?

The most effective approach constructs palindrome numbers first, then checks whether they can be factored into two n-digit numbers. Generating palindromes in descending order guarantees the first valid match is the largest. This avoids checking every possible product and significantly reduces the search space.

Is Largest Palindrome Product asked at Google/Amazon/Meta?

Palindrome and numeric enumeration problems appear frequently in interviews at companies like Google, Amazon, and Meta. Variants of this problem test understanding of number properties, optimization of brute force searches, and mathematical pattern recognition.

What data structure is used in Largest Palindrome Product?

The problem primarily uses mathematical operations and enumeration rather than complex data structures. Integer arithmetic, digit reversal, and divisor checks are the key operations used to generate and validate palindrome candidates.

What is the time complexity of Largest Palindrome Product?

A naive brute force approach takes roughly O(10^(2n)) time because it tests every pair of n-digit numbers. The optimized palindrome-construction approach reduces this to about O(10^n) candidate checks, making it far more practical for the constraint n ≤ 8.

Description Solution Video 17:01

479. Largest Palindrome Product

Hard40.2% acceptance1 company

Given an integer n, return the largest palindromic integer that can be represented as the product of two n-digits integers. Since the answer can be very large, return it modulo 1337.

Example 1:

Input: n = 2
Output: 987
Explanation: 99 x 91 = 9009, 9009 % 1337 = 987

Example 2:

Input: n = 1
Output: 9

Constraints:

1 <= n <= 8

Asked at 1 company

Yahoo

Topics

Enumeration Math

17:01

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1class Solution:
2    def largestPalindrome(self, n: int) -> int:
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