Simple Matrix Practice

Lesson Overview

Welcome to today's lesson covering Simple Matrix Practice . This is where we traverse the arena of two-dimensional data structures, commonly known as matrices . Matrices play an instrumental role in many programming domains, such as machine learning, computer vision, and game development, making it important for you to understand how to effectively manipulate and traverse them.

Quick Example

To explore matrices in Kotlin, it is essential to understand that a matrix is typically represented as a List of Lists or an Array of Arrays . In this structure, each inner list (or array) represents a separate row . Given this structure, we can easily access matrix elements using row and column indices: matrix[rowIndex][columnIndex] . Our practice problems will be based on similar logic, where we traverse and manipulate matrix data. One practical exercise we will cover involves searching for a specific target value within a sorted matrix where each row and column is sorted in ascending order. This exercise enhances your problem-solving skills and deepens your understanding of matrix traversal . Since the matrix is sorted both row-wise and column-wise, we can leverage this property for an efficient search. Start from the top-right corner of the matrix : If the current element equals the target, you have found the value. If the current element is greater than the target, move left (decrease the column index). If the current element is less than the target, move down (increase the row index). Kotlin fun searchMatrix(matrix: List<List<Int>>, target: Int): Boolean {// Guard against empty input if (matrix.isEmpty() || matrix[0].isEmpty()) return false // Start at the top-right corner var row = 0 var col = matrix[0].size - 1 while (row < matrix.size && col >= 0) {val current = matrix[row][col] if (current == target) {return true // Target found} else if (current > target) {col-- // Move left} else {row++ // Move down}} return false // Target not found} fun main() {val matrix = listOf(listOf(1, 4, 7), listOf(2, 5, 8), listOf(3, 6, 9)) val target = 5 println("Target $target found: ${searchMatrix(matrix, target)}")} Continue these steps until you either find the target or exhaust the search space. This method ensures that each step narrows down the potential search area efficiently.

Join the 1M+ learners on CodeSignal

Be a part of our community of 1M+ users who develop and demonstrate their skills on CodeSignal

Simple Matrix Practice

Lesson Overview

Quick Example

Join the 1M+ learners on CodeSignal

What's Next?