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Problem: Find the Length of the Longest Common Prefix

med
30 min
Understand how to determine the longest common prefix length between elements from two integer arrays using hash maps. This lesson helps you apply prefix comparison and hashing strategies to solve problems efficiently in coding interviews.

Statement

You are given two arrays of positive integers, arr1 and arr2.

A prefix of a positive integer is an integer formed by one or more of its digits, starting from the leftmost digit. For example, 123123 is a prefix of 1234512345, while 234 234 is not.

common prefix of two integers aa and bb is an integer cc, such that cc is a prefix of both aa and bb. For example, 56553595655359 and 5655456554 have common prefixes 565565 and 56555655 while 12231223 and 4345643456 do not have a common prefix.

You need to find the length of the longest common prefix between all pairs of integers (x, y) such that x belongs to arr1 and y belongs to arr2.

Return the length of the longest common prefix among all such pairs. If no common prefix exists, return 00.

Note: Common prefixes between elements within the same array do not count.

Constraints:

  • 11 \leq arr1.length, arr2.length 5×104\leq 5 \times 10^4

  • 11 \leq arr1[i], arr2[i] 108\leq 10^8

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Tap here to switch tabs
Problem
Submissions

Problem: Find the Length of the Longest Common Prefix

med
30 min
Understand how to determine the longest common prefix length between elements from two integer arrays using hash maps. This lesson helps you apply prefix comparison and hashing strategies to solve problems efficiently in coding interviews.

Statement

You are given two arrays of positive integers, arr1 and arr2.

A prefix of a positive integer is an integer formed by one or more of its digits, starting from the leftmost digit. For example, 123123 is a prefix of 1234512345, while 234 234 is not.

common prefix of two integers aa and bb is an integer cc, such that cc is a prefix of both aa and bb. For example, 56553595655359 and 5655456554 have common prefixes 565565 and 56555655 while 12231223 and 4345643456 do not have a common prefix.

You need to find the length of the longest common prefix between all pairs of integers (x, y) such that x belongs to arr1 and y belongs to arr2.

Return the length of the longest common prefix among all such pairs. If no common prefix exists, return 00.

Note: Common prefixes between elements within the same array do not count.

Constraints:

  • 11 \leq arr1.length, arr2.length 5×104\leq 5 \times 10^4

  • 11 \leq arr1[i], arr2[i] 108\leq 10^8

Unlock AI-Powered LearningUpgrade to smarter learning with instant explanations of Ask Agent, Personalized Interview Prep, Real-World Projects, 3 AI Mock Interviews per month, and Personalized Paths