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This question is commonly asked for Software Engineer candidates at SoFi during technical interviews.

Find Smallest Common Row Value | SoFi Coding Question

Quick Overview

This question evaluates algorithmic problem-solving skills focused on array processing, intersection across multiple sorted sequences, and time/space complexity analysis.

easy
SoFi
Coding & Algorithms
Software Engineer

Find Smallest Common Row Value

Company: SoFi

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: easy

Interview Round: Technical Screen

You are given a 2D integer matrix where each row is sorted in strictly increasing order. Return the smallest integer that appears in every row. If no such integer exists, return -1. Assumptions: - The matrix contains at least 1 row and 1 column. - All rows have the same length. - Values can be negative or positive. Example: Input: [ [1, 2, 3, 4, 5], [2, 4, 5, 8, 10], [3, 5, 7, 9, 11], [1, 3, 5, 7, 9] ] Output: 5 During the interview, you may also be asked to clarify edge cases and write test methods or unit test cases for your solution.

Quick Answer: This question evaluates algorithmic problem-solving skills focused on array processing, intersection across multiple sorted sequences, and time/space complexity analysis.

You are given a 2D integer matrix where each row is sorted in strictly increasing order. Return the smallest integer that appears in every row. If no such integer exists, return -1. Because each row is sorted, you should aim for a solution that uses that structure instead of comparing every value against every other value blindly.

Constraints

1 <= number of rows <= 1000
1 <= number of columns <= 1000
All rows have the same length
Each row is sorted in strictly increasing order
-10^9 <= matrix[i][j] <= 10^9

Examples

Input: ([[1,2,3,4,5],[2,4,5,8,10],[3,5,7,9,11],[1,3,5,7,9]],)

Expected Output: 5

Explanation: The value 5 appears in every row, and no smaller value does.

Input: ([[-4,-1,0,9]],)

Expected Output: -4

Explanation: With only one row, every value in that row appears in every row. The smallest is -4.

Input: ([[1,2,3],[2,4,6],[4,5,7]],)

Expected Output: -1

Explanation: There is no integer that appears in all three rows.

Input: ([[-3,-1,2,4],[-5,-3,2,8],[-10,-3,0,2]],)

Expected Output: -3

Explanation: Both -3 and 2 appear in every row, so the smallest common value is -3.

Input: ([[7],[7],[7]],)

Expected Output: 7

Explanation: Each row contains only 7, so 7 is the smallest common value.

Input: ([[1,5,10,20],[2,5,12,20],[0,5,15,20]],)

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Quick Overview

Find Smallest Common Row Value

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Examples

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