Note: This article is an improved version of the previous article "C Language Algorithm 1.2: Improved Version of Connectivity Problem [Video Analysis]" , it is recommended to read the previous article before reading this article.
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1. Source
Program 1.3 from the book "Algorithms: Implementation in C (Parts 1-4) 3rd Edition".
Second, the difference between the two versions
Both versions are implemented using arrays. Suppose there is a one-dimensional array a with a size of 10. The values stored in a[0] to a[9] are 0~9 respectively, that is, the value of each element is different. Same.
| version 1.2 | version 1.3 | |
|---|---|---|
| implement logic | Using a tree structure, when merging, merge the tree on the left under the tree on the right. | When using a tree structure, when merging, the tree with a smaller depth is merged under the tree with a larger depth. |
| Advantages and disadvantages | Slow to find, fast to merge | Fast search and fast merge |
3. Schematic diagram of version 1.3
In the previous version 1.2, the tree on the left was always merged into the tree on the right, resulting in an extremely long tree depth, and a lot of queries were required to find the root node.
However, in the current version 1.3, the small tree is always merged into the large tree to achieve a balanced tree depth, so the number of queries required to find the root node is much less.
4. Performance test results
| Number of nodes | Time-consuming version 1.2 (milliseconds) | Version 1.3 takes time (milliseconds) | time-consuming ratio |
|---|---|---|---|
| 10000 | 0 | 0 | neglect |
| 100,000 | 3199 | 2 | 1599 |
| 1000000 | 50522 | 25 | 2020 |
- The performance improvement reaches more than 1000 times.
- The higher the number of nodes, the higher the performance improvement.
Five, source code
There are many source files, so I won’t post them in the article. The links are here: github , gitee
6. Schematic diagram of the process
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