Is Zigzag Grid Traversal With Skip easy or hard?

Zigzag Grid Traversal With Skip is classified as an Easy problem. The main challenge is correctly handling alternating row directions while applying the skip rule consistently across the traversal order.

Zigzag Grid Traversal With Skip Python/Java solution

The implementation is identical across languages: iterate rows, reverse column direction for odd rows, and toggle a skip flag after each visited cell. FleetCode provides full working implementations in Python, Java, C++, Go, and TypeScript.

How to solve Zigzag Grid Traversal With Skip in O(n)?

Treat the traversal as a sequential stream of visited cells produced by a zigzag scan of the matrix. Maintain a boolean flag to alternate between taking and skipping elements. Each step flips the flag, giving an overall O(m*n) traversal with constant extra space.

What is the best approach for Zigzag Grid Traversal With Skip?

The most efficient method is direct simulation of the zigzag traversal. Iterate through the matrix row by row, reversing direction for every alternate row, and maintain a toggle to skip every second visited cell. This runs in O(m*n) time with O(1) additional space.

Is Zigzag Grid Traversal With Skip asked at Google/Amazon/Meta?

Zigzag-style matrix traversal problems frequently appear in interviews at companies like Amazon and Google because they test iteration control and simulation skills. Variants involving diagonals, spiral order, or zigzag patterns are common.

What data structure is used in Zigzag Grid Traversal With Skip?

The solution primarily uses arrays and basic matrix traversal. No advanced data structures are required—just loop control for rows and columns and a boolean variable to track whether the current element should be skipped.

What is the time complexity of Zigzag Grid Traversal With Skip?

The time complexity is O(m*n) because every cell in the grid is visited exactly once during the zigzag traversal. The algorithm only performs constant work per cell. Space complexity is O(1) excluding the output array.

Description Solution Video 8:54

3417. Zigzag Grid Traversal With Skip

Easy64.9% acceptance3 companies

You are given an m x n 2D array grid of positive integers.

Your task is to traverse grid in a zigzag pattern while skipping every alternate cell.

Zigzag pattern traversal is defined as following the below actions:

Start at the top-left cell (0, 0).
Move right within a row until the end of the row is reached.
Drop down to the next row, then traverse left until the beginning of the row is reached.
Continue alternating between right and left traversal until every row has been traversed.

Note that you must skip every alternate cell during the traversal.

Return an array of integers result containing, in order, the value of the cells visited during the zigzag traversal with skips.

Example 1:

Input: grid = [[1,2],[3,4]]

Output: [1,4]

Explanation:

Example 2:

Input: grid = [[2,1],[2,1],[2,1]]

Output: [2,1,2]

Explanation: