Add LinkedList traversal and reverse implementations #194
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"Reverse a linked list" is a popular algorithm challenge. It might be more appropriate to put these functions in a |
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@trekhleb Could you share thoughts on this please? |
| /** | ||
| * The items in the list have been traversed in reverse order | ||
| */ | ||
| reverseTraversal(callback = undefined) { |
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This implementation of reverseTraversal has a running time of O(n^2). It would be more straightforward and more performant (O(n)) to just define reverseTraversal as traverse().reverse().
If you want to write a reverseTraverse function as an algorithm exercise, it might be better to define it recursively, like this:
function reverseTraverse(node, callback) {
if (typeof callback !== 'function') {
throw new TypeError(
`reverseTraverse method requires a callback function as an argument.\nArgument given: ${typeof callback}`
)
}
if (!node) return [];
return reverseTraverse(
node.next, callback
).concat(callback(node.value));
}| .append(2) | ||
| .append(3); | ||
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| const traversedNodes = linkedList.traverse(); |
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linkedList.traverse() should be passed the callback. Also, it should be passed a callback that changes the values, to distinguish it from toArray(). e.g. const callback = (x) => x * 2;
| expect(traversedNodeValues).toEqual([1, 2, 3]); | ||
| }); | ||
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| it('should traverse through all nodes with callback', () => { |
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If you adopt the other changes suggested, this test can be deleted.
Codecov Report
@@ Coverage Diff @@
## master #194 +/- ##
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Coverage 100% 100%
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Files 136 136
Lines 2505 2528 +23
Branches 416 419 +3
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+ Hits 2505 2528 +23
Continue to review full report at Codecov.
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Hi @appleJax, |
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Hi @hanhdt, thank you for PR! I would agree that linked list traversals are worthy to be put in new Meanwhile So I'm going to merge these changes for now and I'll move traversal codes to new section. Thank you for your effort guys! |
* Add LinkedList traverse function * Add LinkedList reverse traversal implementations * Update LinkedList traverse function * Update LinkedList reverse traversal and test cases * Update LinkedList traversal tests
* Add LinkedList traverse function * Add LinkedList reverse traversal implementations * Update LinkedList traverse function * Update LinkedList reverse traversal and test cases * Update LinkedList traversal tests
Changes: