https://github.com/iampavangandhi/wordcompositionproblem
📄 Word Composition Problem - To find words constructed by concatenating shorter words also found in the file.
https://github.com/iampavangandhi/wordcompositionproblem
composition-problem datastructures datastructuresandalgorithm trie word-composition
Last synced: 1 day ago
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📄 Word Composition Problem - To find words constructed by concatenating shorter words also found in the file.
- Host: GitHub
- URL: https://github.com/iampavangandhi/wordcompositionproblem
- Owner: iampavangandhi
- License: mit
- Created: 2020-12-06T16:50:35.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2020-12-06T16:51:40.000Z (almost 5 years ago)
- Last Synced: 2025-03-16T08:28:00.226Z (7 months ago)
- Topics: composition-problem, datastructures, datastructuresandalgorithm, trie, word-composition
- Language: JavaScript
- Homepage:
- Size: 470 KB
- Stars: 0
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Word Composition Problem
To find words constructed by concatenating shorter words also found in the file.
## Input (files)
- words.txt
- words1.txt
## Output
```
ratcatdogcat catsdogcats
ethylenediaminetetraacetates ethylenediaminetetraacetate
```
## Approach
Used Trie data structure its a special tree that stores strings. Maximum number of children of a node is equal to size of alphabet. Trie supports search, insert and delete operations in O(k) time where k is length of key/word. This is obviously faster than BST and Hashing. and we can efficiently do Prefix search.
First `searchConcatWords` function read the file text and constructed Trie from the text/words using insert method present inside `trie.js` then used `findLongestString` function inside a loop to find the longest strings. Then `prefixChecker` function checks the string whether it was constructed using small words found in the Trie or not by checking the length of the result using find method present inside `trie.js` if greater than 1 increment the index and after loop ends return `true` If not there are two cases: (1) If the index is equal to 1 that means concat word is not found in the Trie and return `false` (2) Else it cuts the previous part and recursively call `prefixChecker` function again.
### Example of `prefixChecker` :
| Calling word | Output | Result |
| ------------------ | ---------------------------------------------------- | ------------------------------------------------ |
| trie.find("c") | `[ 'catxdogcatsrat', 'catsdogcats', 'cats', 'cat' ]` | Increment index and return `true` after loop |
| trie.find("catsd") | `[ 'catsdogcats' ]` and `index !== 1` | Recursive call to `prefixChecker` with `dogcats` |
| trie.find("hippo") | `[ 'hippopotamuses' ]` and `index === 1` | Concat word not found and returns `false` |