Mastering Zero Movement in Arrays: A Guide to LeetCode Challenge
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Chapter 1: Understanding the Move Zeroes Problem
In today's LeetCode challenge, we'll tackle the "Move Zeroes" problem. It's essential that readers have a basic grasp of the two-pointer technique before we dive into the solution. If you need a refresher, check out this informative YouTube video:
Problem Statement
The task is clear: given an integer array named nums, your goal is to move all zeros to the end while keeping the relative order of the non-zero elements intact. Importantly, this must be done in-place without creating a copy of the array.
#### Example Scenarios
Example 1:
Input: nums = [0, 1, 0, 3, 12]
Output: [1, 3, 12, 0, 0]
Example 2:
Input: nums = [0]
Output: [0]
Solution Overview
The solution may seem straightforward. Here’s a breakdown of how to approach it:
Check the Array Length:
We start by ensuring that the nums array contains more than one element. If it has one or no elements, executing the algorithm is unnecessary.
Pointer Initialization:
We set up two pointers: startIndex and secondIndex.
Identifying Zeros and Non-Zeros:
Within our loop, we evaluate the element at startIndex. If it’s zero and the element at secondIndex is not, we swap the two values and increment startIndex by one.
Advancing Non-Zeros:
If the value at startIndex is already a non-zero, we simply move the startIndex pointer one step forward.
Iteration Continuation:
After checking a pair of elements, we then move secondIndex by one.
Final Arrangement:
Once the loop has processed the entire array, all zeros will have been shifted to the end while the original order of non-zero elements remains unchanged.
In essence, this algorithm teaches the computer how to reorganize an array by ensuring that all zeros are moved to the end, maintaining the sequence of the non-zero elements.
If you found this solution useful or have any suggestions for improvement, feel free to leave a comment and give it a thumbs up!
Chapter 2: Video Resources
For additional insights, check out these related video tutorials:
The first video titled "LeetCode 30 Day Challenge Day 4: Move Zeroes" provides a comprehensive walkthrough of the algorithm:
The second video, "Move Zeroes - Leetcode 283 - Python," offers a focused Python solution to the same problem: