From d37adadf44537cff90278e061849281595aa2145 Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <mikhail.maksyutin@gmail.com>
Date: Fri, 1 Jun 2018 15:19:27 +0300
Subject: [PATCH 1/8] Fix LinkedList
---
src/data-structures/linked-list/LinkedList.js | 2 +-
src/data-structures/linked-list/__test__/LinkedList.test.js | 5 +++--
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/src/data-structures/linked-list/LinkedList.js b/src/data-structures/linked-list/LinkedList.js
index b428ad7395..4e82ab0d7f 100644
--- a/src/data-structures/linked-list/LinkedList.js
+++ b/src/data-structures/linked-list/LinkedList.js
@@ -60,7 +60,7 @@ export default class LinkedList {
let deletedNode = null;
// If the head must be deleted then make 2nd node to be a head.
- if (this.compare.equal(this.head.value, value)) {
+ while (this.head && this.compare.equal(this.head.value, value)) {
deletedNode = this.head;
this.head = this.head.next;
}
diff --git a/src/data-structures/linked-list/__test__/LinkedList.test.js b/src/data-structures/linked-list/__test__/LinkedList.test.js
index 1b938e1b10..61f018fee6 100644
--- a/src/data-structures/linked-list/__test__/LinkedList.test.js
+++ b/src/data-structures/linked-list/__test__/LinkedList.test.js
@@ -32,6 +32,7 @@ describe('LinkedList', () => {
expect(linkedList.delete(5)).toBeNull();
+ linkedList.append(1);
linkedList.append(1);
linkedList.append(2);
linkedList.append(3);
@@ -45,10 +46,10 @@ describe('LinkedList', () => {
const deletedNode = linkedList.delete(3);
expect(deletedNode.value).toBe(3);
- expect(linkedList.toString()).toBe('1,2,4,5');
+ expect(linkedList.toString()).toBe('1,1,2,4,5');
linkedList.delete(3);
- expect(linkedList.toString()).toBe('1,2,4,5');
+ expect(linkedList.toString()).toBe('1,1,2,4,5');
linkedList.delete(1);
expect(linkedList.toString()).toBe('2,4,5');
From 8d85d3d443d34ff383fd52762f8efff059aac85c Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <m.maksyutin@gmail.com>
Date: Sun, 3 Jun 2018 14:17:42 +0300
Subject: [PATCH 2/8] Fix the prepend method for the LinkedList
---
src/data-structures/linked-list/LinkedList.js | 8 +++++++-
.../linked-list/__test__/LinkedList.test.js | 8 ++++++--
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/src/data-structures/linked-list/LinkedList.js b/src/data-structures/linked-list/LinkedList.js
index 4e82ab0d7f..7d330f7bfd 100644
--- a/src/data-structures/linked-list/LinkedList.js
+++ b/src/data-structures/linked-list/LinkedList.js
@@ -21,7 +21,13 @@ export default class LinkedList {
*/
prepend(value) {
// Make new node to be a head.
- this.head = new LinkedListNode(value, this.head);
+ const newNode = new LinkedListNode(value, this.head);
+ this.head = newNode;
+
+ // If there is no tail yet let's make new node a tail.
+ if (!this.tail) {
+ this.tail = newNode;
+ }
return this;
}
diff --git a/src/data-structures/linked-list/__test__/LinkedList.test.js b/src/data-structures/linked-list/__test__/LinkedList.test.js
index 61f018fee6..384e44fa5b 100644
--- a/src/data-structures/linked-list/__test__/LinkedList.test.js
+++ b/src/data-structures/linked-list/__test__/LinkedList.test.js
@@ -21,10 +21,14 @@ describe('LinkedList', () => {
it('should prepend node to linked list', () => {
const linkedList = new LinkedList();
- linkedList.append(1);
linkedList.prepend(2);
+ expect(linkedList.head.toString()).toBe('2');
+ expect(linkedList.tail.toString()).toBe('2');
+
+ linkedList.append(1);
+ linkedList.prepend(3);
- expect(linkedList.toString()).toBe('2,1');
+ expect(linkedList.toString()).toBe('3,2,1');
});
it('should delete node by value from linked list', () => {
From efe4f8119224e95c170c6c51ed038c6cf6a2b46c Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <m.maksyutin@gmail.com>
Date: Mon, 4 Jun 2018 11:38:26 +0300
Subject: [PATCH 3/8] Fix the remove method for the MinHeap
---
src/data-structures/heap/MinHeap.js | 2 +-
.../heap/__test__/MinHeap.test.js | 22 +++++++++++++++++++
2 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/src/data-structures/heap/MinHeap.js b/src/data-structures/heap/MinHeap.js
index bf23f415dd..5f32f53f74 100644
--- a/src/data-structures/heap/MinHeap.js
+++ b/src/data-structures/heap/MinHeap.js
@@ -141,8 +141,8 @@ export default class MinHeap {
*/
remove(item, customFindingComparator) {
// Find number of items to remove.
- const numberOfItemsToRemove = this.find(item).length;
const customComparator = customFindingComparator || this.compare;
+ const numberOfItemsToRemove = this.find(item, customComparator).length;
for (let iteration = 0; iteration < numberOfItemsToRemove; iteration += 1) {
// We need to find item index to remove each time after removal since
diff --git a/src/data-structures/heap/__test__/MinHeap.test.js b/src/data-structures/heap/__test__/MinHeap.test.js
index f4ce4ac381..b2b8a7b157 100644
--- a/src/data-structures/heap/__test__/MinHeap.test.js
+++ b/src/data-structures/heap/__test__/MinHeap.test.js
@@ -1,4 +1,5 @@
import MinHeap from '../MinHeap';
+import Comparator from '../../../utils/comparator/Comparator';
describe('MinHeap', () => {
it('should create an empty min heap', () => {
@@ -147,4 +148,25 @@ describe('MinHeap', () => {
expect(minHeap.remove(3).toString()).toEqual('4');
expect(minHeap.remove(4).toString()).toEqual('');
});
+
+ it('should be possible to remove items from heap with custom finding comparator', () => {
+ const minHeap = new MinHeap();
+ minHeap.add('dddd');
+ minHeap.add('ccc');
+ minHeap.add('bb');
+ minHeap.add('a');
+
+ expect(minHeap.toString()).toBe('a,bb,ccc,dddd');
+
+ const comparator = new Comparator((a, b) => {
+ if (a.length === b.length) {
+ return 0;
+ }
+
+ return a.length < b.length ? -1 : 1;
+ });
+
+ minHeap.remove('hey', comparator);
+ expect(minHeap.toString()).toBe('a,bb,dddd');
+ });
});
From eae4e5c13bc6e6140dc813e1f2cb0526eb3d1d55 Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <m.maksyutin@gmail.com>
Date: Wed, 13 Jun 2018 17:53:47 +0300
Subject: [PATCH 4/8] Correct a comment
---
src/data-structures/tree/BinaryTreeNode.js | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/data-structures/tree/BinaryTreeNode.js b/src/data-structures/tree/BinaryTreeNode.js
index 71e7ae0d3f..9205e4820e 100644
--- a/src/data-structures/tree/BinaryTreeNode.js
+++ b/src/data-structures/tree/BinaryTreeNode.js
@@ -69,7 +69,7 @@ export default class BinaryTreeNode {
return undefined;
}
- // Check if grand-parent has more than two children.
+ // Check if grand-parent has two children.
if (!this.parent.parent.left || !this.parent.parent.right) {
return undefined;
}
From a2c30129afbbb591c790ec659df7f723feccc0a5 Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <m.maksyutin@gmail.com>
Date: Tue, 19 Jun 2018 10:57:02 +0300
Subject: [PATCH 5/8] Fix BST removal method
---
.../binary-search-tree/BinarySearchTreeNode.js | 18 +++++++++++-------
.../__test__/BinarySearchTreeNode.test.js | 15 +++++++++++++++
2 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js b/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js
index 9ad74483da..06d99e431b 100644
--- a/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js
+++ b/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js
@@ -94,8 +94,13 @@ export default class BinarySearchTreeNode extends BinaryTreeNode {
if (!nodeToRemove.left && !nodeToRemove.right) {
// Node is a leaf and thus has no children.
- // Just remove the pointer to this node from the parent node.
- parent.removeChild(nodeToRemove);
+ if (parent) {
+ // Node has a parent. Just remove the pointer to this node from the parent.
+ parent.removeChild(nodeToRemove);
+ } else {
+ // Node has no parent. Just erase current node value.
+ nodeToRemove.value = null;
+ }
} else if (nodeToRemove.left && nodeToRemove.right) {
// Node has two children.
// Find the next biggest value (minimum value in the right branch)
@@ -113,11 +118,10 @@ export default class BinarySearchTreeNode extends BinaryTreeNode {
} else {
// Node has only one child.
// Make this child to be a direct child of current node's parent.
- if (nodeToRemove.left) {
- parent.replaceChild(nodeToRemove, nodeToRemove.left);
- } else {
- parent.replaceChild(nodeToRemove, nodeToRemove.right);
- }
+ const child = nodeToRemove.left || nodeToRemove.right;
+ nodeToRemove.value = child.value;
+ nodeToRemove.setLeft(child.left);
+ nodeToRemove.setRight(child.right);
}
return true;
diff --git a/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js b/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js
index a353c1f1e1..63b9d999d6 100644
--- a/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js
+++ b/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js
@@ -185,6 +185,21 @@ describe('BinarySearchTreeNode', () => {
expect(bstRootNode.toString()).toBe('30');
});
+ it('should remove node with no parent', () => {
+ const bstRootNode = new BinarySearchTreeNode();
+ expect(bstRootNode.toString()).toBe('');
+
+ bstRootNode.insert(1);
+ bstRootNode.insert(2);
+ expect(bstRootNode.toString()).toBe('1,2');
+
+ bstRootNode.remove(1);
+ expect(bstRootNode.toString()).toBe('2');
+
+ bstRootNode.remove(2);
+ expect(bstRootNode.toString()).toBe('');
+ });
+
it('should throw error when trying to remove not existing node', () => {
const bstRootNode = new BinarySearchTreeNode();
From 35f7b89e16aabd934660356298f2e95e350c74e1 Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <m.maksyutin@gmail.com>
Date: Mon, 25 Jun 2018 11:05:54 +0300
Subject: [PATCH 6/8] Fix the findEdge method of the graph
---
src/data-structures/graph/Graph.js | 3 +++
src/data-structures/graph/__test__/Graph.test.js | 8 ++++++--
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/src/data-structures/graph/Graph.js b/src/data-structures/graph/Graph.js
index e2ef20b7e0..8e603c389b 100644
--- a/src/data-structures/graph/Graph.js
+++ b/src/data-structures/graph/Graph.js
@@ -115,6 +115,9 @@ export default class Graph {
*/
findEdge(startVertex, endVertex) {
const vertex = this.getVertexByKey(startVertex.getKey());
+ if (!vertex) {
+ return null;
+ }
return vertex.findEdge(endVertex);
}
diff --git a/src/data-structures/graph/__test__/Graph.test.js b/src/data-structures/graph/__test__/Graph.test.js
index 1c6592ba55..be6e9d7fb2 100644
--- a/src/data-structures/graph/__test__/Graph.test.js
+++ b/src/data-structures/graph/__test__/Graph.test.js
@@ -87,9 +87,11 @@ describe('Graph', () => {
const graphEdgeAB = graph.findEdge(vertexA, vertexB);
const graphEdgeBA = graph.findEdge(vertexB, vertexA);
- const graphEdgeAC = graph.findEdge(vertexB, vertexC);
+ const graphEdgeAC = graph.findEdge(vertexA, vertexC);
+ const graphEdgeCA = graph.findEdge(vertexC, vertexA);
expect(graphEdgeAC).toBeNull();
+ expect(graphEdgeCA).toBeNull();
expect(graphEdgeAB).toEqual(edgeAB);
expect(graphEdgeBA).toEqual(edgeAB);
expect(graphEdgeAB.weight).toBe(10);
@@ -108,9 +110,11 @@ describe('Graph', () => {
const graphEdgeAB = graph.findEdge(vertexA, vertexB);
const graphEdgeBA = graph.findEdge(vertexB, vertexA);
- const graphEdgeAC = graph.findEdge(vertexB, vertexC);
+ const graphEdgeAC = graph.findEdge(vertexA, vertexC);
+ const graphEdgeCA = graph.findEdge(vertexC, vertexA);
expect(graphEdgeAC).toBeNull();
+ expect(graphEdgeCA).toBeNull();
expect(graphEdgeBA).toBeNull();
expect(graphEdgeAB).toEqual(edgeAB);
expect(graphEdgeAB.weight).toBe(10);
From 48790e9546ead6c9d211ff868d395846bc1e479f Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <m.maksyutin@gmail.com>
Date: Mon, 25 Jun 2018 18:16:43 +0300
Subject: [PATCH 7/8] Fix the value returned by DisjointSet union
---
src/data-structures/disjoint-set/DisjointSet.js | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/data-structures/disjoint-set/DisjointSet.js b/src/data-structures/disjoint-set/DisjointSet.js
index 2952f0a1b8..2fe3c25c3c 100644
--- a/src/data-structures/disjoint-set/DisjointSet.js
+++ b/src/data-structures/disjoint-set/DisjointSet.js
@@ -70,7 +70,7 @@ export default class DisjointSet {
// If rootB's tree is bigger then make rootB to be a new root.
rootB.addChild(rootA);
- return rootB.getKey();
+ return this;
}
// If rootA's tree is bigger then make rootA to be a new root.
From 3331115575501d8bec469d1cee228110f1d16f52 Mon Sep 17 00:00:00 2001
From: "m.maksyutin" <m.maksyutin@gmail.com>
Date: Thu, 28 Jun 2018 16:37:40 +0300
Subject: [PATCH 8/8] Add recursive factorial function
---
.../factorial/__test__/factorialRecursive.test.js | 11 +++++++++++
src/algorithms/math/factorial/factorialRecursive.js | 7 +++++++
2 files changed, 18 insertions(+)
create mode 100644 src/algorithms/math/factorial/__test__/factorialRecursive.test.js
create mode 100644 src/algorithms/math/factorial/factorialRecursive.js
diff --git a/src/algorithms/math/factorial/__test__/factorialRecursive.test.js b/src/algorithms/math/factorial/__test__/factorialRecursive.test.js
new file mode 100644
index 0000000000..9029faee0a
--- /dev/null
+++ b/src/algorithms/math/factorial/__test__/factorialRecursive.test.js
@@ -0,0 +1,11 @@
+import factorialRecursive from '../factorialRecursive';
+
+describe('factorialRecursive', () => {
+ it('should calculate factorial', () => {
+ expect(factorialRecursive(0)).toBe(1);
+ expect(factorialRecursive(1)).toBe(1);
+ expect(factorialRecursive(5)).toBe(120);
+ expect(factorialRecursive(8)).toBe(40320);
+ expect(factorialRecursive(10)).toBe(3628800);
+ });
+});
diff --git a/src/algorithms/math/factorial/factorialRecursive.js b/src/algorithms/math/factorial/factorialRecursive.js
new file mode 100644
index 0000000000..e2b4aec6c9
--- /dev/null
+++ b/src/algorithms/math/factorial/factorialRecursive.js
@@ -0,0 +1,7 @@
+/**
+ * @param {number} number
+ * @return {number}
+ */
+export default function factorialRecursive(number) {
+ return number > 1 ? number * factorialRecursive(number - 1) : 1;
+}