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Commit 99f807f

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committed
add Queue class, and requisite unit tests
1 parent 9f99008 commit 99f807f

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8 files changed

+316
-7
lines changed

8 files changed

+316
-7
lines changed

‎dist/datastructures/DoublyLinkedList.js

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,7 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
44
};
55
Object.defineProperty(exports, "__esModule", { value: true });
66
const SinglyLinkedList_1 = __importDefault(require("./SinglyLinkedList"));
7+
const IndexError_1 = __importDefault(require("../utils/IndexError"));
78
class DoublyLinkedList extends SinglyLinkedList_1.default {
89
constructor() {
910
super();
@@ -54,7 +55,7 @@ class DoublyLinkedList extends SinglyLinkedList_1.default {
5455
else {
5556
// count backwards from tail
5657
if (!this.tail || (index > this.length - 1 || index < 0))
57-
returnnull;
58+
thrownewIndexError_1.default('list index out of range.');
5859
let counter = this.length - 1;
5960
let node = this.tail;
6061
while (counter > index) {

‎dist/datastructures/Queue.js

Lines changed: 86 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,86 @@
1+
"use strict";
2+
var __importDefault = (this && this.__importDefault) || function (mod) {
3+
return (mod && mod.__esModule) ? mod : { "default": mod };
4+
};
5+
Object.defineProperty(exports, "__esModule", { value: true });
6+
const Node_1 = __importDefault(require("./Node"));
7+
const IndexError_1 = __importDefault(require("../utils/IndexError"));
8+
class Queue {
9+
constructor() {
10+
this.enqueue = (value) => {
11+
const oldBack = this.back;
12+
const node = new Node_1.default(value);
13+
// add node to end of list
14+
// O(1) since we keep track of tail node
15+
if (!this.front || !this.back) {
16+
this.front = node;
17+
}
18+
else {
19+
this.back.next = node;
20+
}
21+
this.back = node;
22+
this._length++;
23+
node.prev = oldBack;
24+
return node;
25+
};
26+
this.dequeue = () => {
27+
if (this.front && this.front.next) {
28+
this.front.next.prev = null;
29+
}
30+
if (!this.front)
31+
return;
32+
const newFront = this.front.next;
33+
const oldFront = this.front;
34+
oldFront.next = null;
35+
this.front = newFront || null;
36+
if (this.length === 1)
37+
this.back = null;
38+
this._length--;
39+
return oldFront;
40+
};
41+
this.get = (index) => {
42+
if (index < (this.length / 2)) {
43+
// start at front
44+
if (!this.front || (index > this.length - 1 || index < 0))
45+
throw new IndexError_1.default('list index out of range.');
46+
let counter = 0;
47+
let node = this.front;
48+
while (counter < index) {
49+
if (!node.next)
50+
return null;
51+
node = node.next;
52+
counter++;
53+
}
54+
return node;
55+
}
56+
else {
57+
// count from back
58+
if (!this.back || (index > this.length - 1 || index < 0))
59+
throw new IndexError_1.default('list index out of range.');
60+
let counter = this.length - 1;
61+
let node = this.back;
62+
while (counter > index) {
63+
if (!node.prev)
64+
return null;
65+
node = node.prev;
66+
counter--;
67+
}
68+
return node;
69+
}
70+
};
71+
this.set = (value, index) => {
72+
const selectedNode = this.get(index);
73+
if (selectedNode) {
74+
selectedNode.data = value;
75+
}
76+
return selectedNode;
77+
};
78+
this._length = 0;
79+
this.back = null;
80+
this.front = null;
81+
}
82+
get length() {
83+
return this._length;
84+
}
85+
}
86+
exports.default = Queue;

‎dist/datastructures/Queue.test.js

Lines changed: 60 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,60 @@
1+
"use strict";
2+
var __importDefault = (this && this.__importDefault) || function (mod) {
3+
return (mod && mod.__esModule) ? mod : { "default": mod };
4+
};
5+
Object.defineProperty(exports, "__esModule", { value: true });
6+
const Queue_1 = __importDefault(require("./Queue"));
7+
let queue = new Queue_1.default();
8+
beforeEach(() => queue = new Queue_1.default());
9+
describe('base functionality', () => {
10+
test('queue class exists', () => {
11+
expect(typeof queue).toBe('object');
12+
});
13+
test('enqueue method exists', () => {
14+
expect(queue.enqueue).toBeTruthy();
15+
});
16+
test('dequeue method exists', () => {
17+
expect(queue.dequeue).toBeTruthy();
18+
});
19+
test('get method exists', () => {
20+
expect(queue.get).toBeTruthy();
21+
});
22+
test('set method exists', () => {
23+
expect(queue.set).toBeTruthy();
24+
});
25+
test('enqueue method works', () => {
26+
var _a, _b;
27+
queue.enqueue('1');
28+
queue.enqueue('2');
29+
queue.enqueue('3');
30+
expect(queue).toHaveLength(3);
31+
expect((_a = queue.back) === null || _a === void 0 ? void 0 : _a.data).toBe('3');
32+
expect((_b = queue.front) === null || _b === void 0 ? void 0 : _b.data).toBe('1');
33+
});
34+
test('dequeue method works', () => {
35+
var _a, _b;
36+
expect(queue.dequeue()).toBeUndefined();
37+
queue.enqueue('1');
38+
queue.enqueue('2');
39+
queue.enqueue('3');
40+
queue.dequeue();
41+
expect(queue).toHaveLength(2);
42+
expect((_a = queue.back) === null || _a === void 0 ? void 0 : _a.data).toBe('3');
43+
expect((_b = queue.front) === null || _b === void 0 ? void 0 : _b.data).toBe('2');
44+
});
45+
test('get and set methods work', () => {
46+
var _a, _b;
47+
try {
48+
queue.set('Mad Hatter', 1);
49+
}
50+
catch (e) {
51+
expect(e).toBeTruthy();
52+
}
53+
queue.enqueue('March Hare');
54+
queue.set('The Dormouse', 0);
55+
queue.set('Alice', 0);
56+
expect((_a = queue.front) === null || _a === void 0 ? void 0 : _a.data).toBe('Alice');
57+
expect((_b = queue.back) === null || _b === void 0 ? void 0 : _b.data).toBe('Alice');
58+
expect(queue).toHaveLength(1);
59+
});
60+
});

‎dist/datastructures/Stack.test.js

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -11,19 +11,26 @@ describe('base functionality', () => {
1111
test('stack class exists', () => {
1212
expect(typeof stack).toBe('object');
1313
});
14-
test('can unshift onto stack', () => {
14+
test('can push onto stack', () => {
1515
stack.push(`push: 0`);
1616
expect(stack.head).toBeTruthy();
1717
expect(stack.tail).toBeTruthy();
1818
expect(stack.head.data).toBe(`push: 0`);
1919
expect(stack.tail.data).toBe(`push: 0`);
2020
});
21+
test(`popping from stack gets last item pushed`, () => {
22+
stack.push('Walrus');
23+
stack.push('Orca');
24+
stack.push('Leopard seal');
25+
const poppedNode = stack.pop();
26+
expect(poppedNode).toBeTruthy();
27+
expect(poppedNode.data).toBe('Leopard seal');
28+
});
2129
test('get value of node with get method', () => {
2230
var _a, _b;
2331
stack = SinglyLinkedList_test_1.fillListWithDummyData(stack);
2432
const thirdNodeFromTop = stack.get(2);
2533
expect(thirdNodeFromTop).toBe((_b = (_a = stack.head) === null || _a === void 0 ? void 0 : _a.next) === null || _b === void 0 ? void 0 : _b.next);
26-
// console.log(stack.get(5))
2734
});
2835
test('able to set value of a node by index (distance from the top)', () => {
2936
var _a;

‎src/datastructures/DoublyLinkedList.ts

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
11
import _Node from "./Node";
22
import SinglyLinkedList from './SinglyLinkedList';
3+
import IndexError from '../utils/IndexError';
34

45
class DoublyLinkedList<T> extends SinglyLinkedList<T> {
56
constructor() {
@@ -53,7 +54,7 @@ class DoublyLinkedList<T> extends SinglyLinkedList<T> {
5354
}
5455
else {
5556
// count backwards from tail
56-
if (!this.tail || (index > this.length - 1 || index < 0)) returnnull;
57+
if (!this.tail || (index > this.length - 1 || index < 0)) thrownewIndexError('list index out of range.');
5758
let counter = this.length - 1;
5859
let node = this.tail;
5960
while (counter > index) {

‎src/datastructures/Queue.test.ts

Lines changed: 59 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,59 @@
1+
import randomRange from '../utils/randomRange';
2+
import { fillListWithDummyData } from './SinglyLinkedList.test';
3+
import { testTraversalDLL } from './DoublyLinkedList.test';
4+
import _Node from './Node';
5+
import Queue from './Queue';
6+
7+
let queue = new Queue<string>();
8+
beforeEach(() => queue = new Queue<string>());
9+
10+
describe('base functionality', () => {
11+
test('queue class exists', () => {
12+
expect(typeof queue).toBe('object')
13+
});
14+
test('enqueue method exists', () => {
15+
expect(queue.enqueue).toBeTruthy()
16+
});
17+
test('dequeue method exists', () => {
18+
expect(queue.dequeue).toBeTruthy()
19+
});
20+
test('get method exists', () => {
21+
expect(queue.get).toBeTruthy()
22+
});
23+
test('set method exists', () => {
24+
expect(queue.set).toBeTruthy()
25+
});
26+
test('enqueue method works', () => {
27+
queue.enqueue('1');
28+
queue.enqueue('2');
29+
queue.enqueue('3');
30+
expect(queue).toHaveLength(3);
31+
expect(queue.back?.data).toBe('3');
32+
expect(queue.front?.data).toBe('1');
33+
});
34+
test('dequeue method works', () => {
35+
expect(queue.dequeue()).toBeUndefined();
36+
queue.enqueue('1');
37+
queue.enqueue('2');
38+
queue.enqueue('3');
39+
queue.dequeue();
40+
expect(queue).toHaveLength(2);
41+
expect(queue.back?.data).toBe('3');
42+
expect(queue.front?.data).toBe('2');
43+
});
44+
45+
test('get and set methods work', () => {
46+
try {
47+
queue.set('Mad Hatter', 1);
48+
}
49+
catch (e) {
50+
expect(e).toBeTruthy();
51+
}
52+
queue.enqueue('March Hare');
53+
queue.set('The Dormouse', 0);
54+
queue.set('Alice', 0);
55+
expect(queue.front?.data).toBe('Alice');
56+
expect(queue.back?.data).toBe('Alice');
57+
expect(queue).toHaveLength(1);
58+
})
59+
})

‎src/datastructures/Queue.ts

Lines changed: 88 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,88 @@
1+
import _Node from './Node';
2+
import IndexError from '../utils/IndexError';
3+
4+
interface Queue<T> {
5+
front: null | _Node<T>;
6+
back: null | _Node<T>;
7+
}
8+
9+
10+
class Queue<T> {
11+
private _length: number;
12+
constructor() {
13+
this._length = 0;
14+
this.back = null;
15+
this.front = null;
16+
}
17+
18+
public get length(): number {
19+
return this._length;
20+
}
21+
22+
enqueue = (value: T): _Node<T> => {
23+
const oldBack = this.back;
24+
const node = new _Node(value);
25+
// add node to end of list
26+
// O(1) since we keep track of tail node
27+
if (!this.front || !this.back) {
28+
this.front = node;
29+
} else {
30+
this.back.next = node;
31+
}
32+
this.back = node;
33+
this._length++;
34+
node.prev = oldBack;
35+
return node;
36+
}
37+
38+
dequeue = (): _Node<T> | void => {
39+
if (this.front && this.front.next) {
40+
this.front.next.prev = null;
41+
}
42+
if (!this.front) return;
43+
const newFront = this.front.next;
44+
const oldFront = this.front;
45+
oldFront.next = null;
46+
this.front = newFront || null;
47+
if (this.length === 1) this.back = null;
48+
this._length--;
49+
return oldFront;
50+
}
51+
52+
get = (index: number): _Node<T> | null => {
53+
if (index < (this.length / 2)) {
54+
// start at front
55+
if (!this.front || (index > this.length - 1 || index < 0)) throw new IndexError('list index out of range.');
56+
let counter = 0;
57+
let node = this.front;
58+
while (counter < index) {
59+
if (!node.next) return null;
60+
node = node.next;
61+
counter++;
62+
}
63+
return node;
64+
}
65+
else {
66+
// count from back
67+
if (!this.back || (index > this.length - 1 || index < 0)) throw new IndexError('list index out of range.');
68+
let counter = this.length - 1;
69+
let node = this.back;
70+
while (counter > index) {
71+
if (!node.prev) return null;
72+
node = node.prev;
73+
counter--;
74+
}
75+
return node;
76+
}
77+
}
78+
79+
set = (value: T, index: number): _Node<T> | null => {
80+
const selectedNode = this.get(index);
81+
if (selectedNode) {
82+
selectedNode.data = value;
83+
}
84+
return selectedNode;
85+
}
86+
}
87+
88+
export default Queue;

‎src/datastructures/Stack.test.ts

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
1-
import randomRange from '../utils/randomRange';
21
import { fillListWithDummyData, testTraversalSLL } from './SinglyLinkedList.test';
32
import Stack from './Stack';
3+
import _Node from './Node';
44

55
let stack = new Stack<string>();
66
beforeEach(() => stack = new Stack<string>());
@@ -9,18 +9,25 @@ describe('base functionality', () => {
99
test('stack class exists', () => {
1010
expect(typeof stack).toBe('object');
1111
});
12-
test('can unshift onto stack', () => {
12+
test('can push onto stack', () => {
1313
stack.push(`push: 0`);
1414
expect(stack.head).toBeTruthy();
1515
expect(stack.tail).toBeTruthy();
1616
expect(stack.head!.data).toBe(`push: 0`)
1717
expect(stack.tail!.data).toBe(`push: 0`);
1818
});
19+
test(`popping from stack gets last item pushed`, () => {
20+
stack.push('Walrus');
21+
stack.push('Orca');
22+
stack.push('Leopard seal');
23+
const poppedNode = stack.pop() as _Node<string>;
24+
expect(poppedNode).toBeTruthy();
25+
expect(poppedNode.data).toBe('Leopard seal')
26+
})
1927
test('get value of node with get method', () => {
2028
stack = fillListWithDummyData(stack);
2129
const thirdNodeFromTop = stack.get(2);
2230
expect(thirdNodeFromTop).toBe(stack.head?.next?.next)
23-
// console.log(stack.get(5))
2431
})
2532
test('able to set value of a node by index (distance from the top)', () => {
2633
stack = fillListWithDummyData(stack);

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