From Insertion Sort to Quick Sort: A Beginner's Comparison of Sorting Algorithms
Sorting algorithms are methods to convert unordered data into ordered sequences. They are fundamental core algorithms in computer science, enabling optimization of subsequent operations such as searching and statistics. This article introduces four typical sorting algorithms: Insertion sort is similar to sorting playing cards, gradually building an ordered sequence. It has a time complexity of O(n²), space complexity of O(1), is stable, and is suitable for small-scale or nearly ordered data. Bubble sort involves comparing and swapping adjacent elements, allowing larger elements to "bubble up". It also has O(n²) time complexity, is stable but inefficient, and is only suitable for extremely small-scale data or educational purposes. Merge sort is based on the divide-and-conquer principle, decomposing arrays and merging ordered subarrays. It has O(n log n) time complexity, O(n) space complexity, is stable, and is suitable for large-scale data or scenarios requiring high stability. Quick sort combines divide-and-conquer with pivot partitioning. It has an average time complexity of O(n log n), O(log n) space complexity, is unstable, and is the most commonly used efficient algorithm in engineering, suitable for large-scale data. The article compares and summarizes the time complexity, space complexity, stability, and applicable scenarios of these algorithms. It suggests that beginners first understand the core ideas, learn from simple to complex cases gradually, and deepen their understanding through hands-on simulation.
Read MoreBubble, Selection, Insertion Sort: Who is the Entry-Level 'Sorting King'?
This article introduces the significance of sorting and three basic sorting algorithms. Sorting is a fundamental operation that rearranges data according to rules to achieve a more ordered state, and it is a prerequisite for understanding complex algorithms. The core ideas and characteristics of the three algorithms are as follows: Bubble Sort repeatedly "bubbles" the largest number to the end through multiple passes, with an intuitive logic but frequent swaps, having a time complexity of O(n²). Selection Sort selects the smallest number in each round and inserts it, with fewer swaps but instability, also with O(n²) complexity. Insertion Sort is similar to arranging playing cards, suitable for small-scale or nearly ordered data, and its complexity is close to O(n). Although these three algorithms are simple, they form the foundation of more complex sorts (such as Heap Sort and Merge Sort). For beginners, it is more important to grasp the core ideas of "selecting the smallest, inserting appropriately, and bubbling the largest," and to understand the thinking of "gradually building an ordered sequence," rather than getting caught up in efficiency. This is the key to understanding the essence of sorting.
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