Commit bd5a16b

m-maksyutintrekhleb

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Fix BST removal method (trekhleb#74)

* Fix LinkedList * Fix the prepend method for the LinkedList * Fix the remove method for the MinHeap * Correct a comment * Fix BST removal method

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+26

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lines changed

src/data-structures/tree/binary-search-tree
- BinarySearchTreeNode.js
- __test__
  - BinarySearchTreeNode.test.js

+26

-7

lines changed

Lines changed: 11 additions & 7 deletions

Original file line number	Diff line number	Diff line change
`@@ -94,8 +94,13 @@ export default class BinarySearchTreeNode extends BinaryTreeNode {`
`94`	`94`
`95`	`95`	`if (!nodeToRemove.left && !nodeToRemove.right) {`
`96`	`96`	`// Node is a leaf and thus has no children.`
`97`		`- // Just remove the pointer to this node from the parent node.`
`98`		`- parent.removeChild(nodeToRemove);`
	`97`	`+ if (parent) {`
	`98`	`+ // Node has a parent. Just remove the pointer to this node from the parent.`
	`99`	`+ parent.removeChild(nodeToRemove);`
	`100`	`+ } else {`
	`101`	`+ // Node has no parent. Just erase current node value.`
	`102`	`+ nodeToRemove.value = null;`
	`103`	`+ }`
`99`	`104`	`} else if (nodeToRemove.left && nodeToRemove.right) {`
`100`	`105`	`// Node has two children.`
`101`	`106`	`// Find the next biggest value (minimum value in the right branch)`
`@@ -113,11 +118,10 @@ export default class BinarySearchTreeNode extends BinaryTreeNode {`
`113`	`118`	`} else {`
`114`	`119`	`// Node has only one child.`
`115`	`120`	`// Make this child to be a direct child of current node's parent.`
`116`		`- if (nodeToRemove.left) {`
`117`		`- parent.replaceChild(nodeToRemove, nodeToRemove.left);`
`118`		`- } else {`
`119`		`- parent.replaceChild(nodeToRemove, nodeToRemove.right);`
`120`		`- }`
	`121`	`+ const child = nodeToRemove.left \|\| nodeToRemove.right;`
	`122`	`+ nodeToRemove.value = child.value;`
	`123`	`+ nodeToRemove.setLeft(child.left);`
	`124`	`+ nodeToRemove.setRight(child.right);`
`121`	`125`	`}`
`122`	`126`
`123`	`127`	`return true;`

Lines changed: 15 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -185,6 +185,21 @@ describe('BinarySearchTreeNode', () => {`
`185`	`185`	`expect(bstRootNode.toString()).toBe('30');`
`186`	`186`	`});`
`187`	`187`
	`188`	`+ it('should remove node with no parent', () => {`
	`189`	`+ const bstRootNode = new BinarySearchTreeNode();`
	`190`	`+ expect(bstRootNode.toString()).toBe('');`
	`191`	`+`
	`192`	`+ bstRootNode.insert(1);`
	`193`	`+ bstRootNode.insert(2);`
	`194`	`+ expect(bstRootNode.toString()).toBe('1,2');`
	`195`	`+`
	`196`	`+ bstRootNode.remove(1);`
	`197`	`+ expect(bstRootNode.toString()).toBe('2');`
	`198`	`+`
	`199`	`+ bstRootNode.remove(2);`
	`200`	`+ expect(bstRootNode.toString()).toBe('');`
	`201`	`+ });`
	`202`	`+`
`188`	`203`	`it('should throw error when trying to remove not existing node', () => {`
`189`	`204`	`const bstRootNode = new BinarySearchTreeNode();`
`190`	`205`

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