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add 10 easy problems
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‎README.md

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# JavaScript
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# TypeScript
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Implementations of LeetCode problem solutions in JavaScript.
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Implementations of LeetCode problem solutions in TypeScript.

‎benchmarks/easy.ts

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@@ -2,4 +2,8 @@ import * as easy from "../src/easy.ts";
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Deno.bench("twoSum", () => {
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easy.twoSum([2, 7, 11, 15], 9)
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});
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Deno.bench("palindromeNumber", () => {
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easy.palindromeNumber(123321);
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});

‎src/easy.ts

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import type { ListNode } from "./utils.ts";
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/**
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* Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
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* You may assume that each input would have exactly one solution, and you may not use the same element twice.
@@ -44,3 +45,173 @@ export function twoSum(nums: number[], target: number): number[] {
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}
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return [];
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}
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export function palindromeNumber(x: number): boolean {
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const num = x;
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if (x < 0) return false;
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let ans = 0;
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while (x > 0) {
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const last_digit = x % 10;
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ans = ans * 10 + last_digit;
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x = Math.floor(x / 10);
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}
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return num === ans;
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}
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export function romanToInteger(s: string): number {
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const multipliers: { [key: string]: number } = {
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IV: 4,
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IX: 9,
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XL: 40,
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XC: 90,
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CD: 400,
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CM: 900,
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I: 1,
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V: 5,
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X: 10,
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L: 50,
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C: 100,
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D: 500,
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M: 1000,
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};
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const tokens = Object.keys(multipliers);
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function next(): string {
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for (const token of tokens) {
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if (s.startsWith(token)) {
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s = s.substring(token.length);
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return token;
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}
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}
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throw new Error(`Unknown token: $(s)`);
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}
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const chars: string[] = [];
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while (s.length > 0) chars.push(next());
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return chars.reduce((sum, char) => {
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return sum += multipliers[char];
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}, 0);
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}
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export function longestCommonPrefix(strs: string[]): string {
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let prefix = strs[0];
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for (let i = 1; i < strs.length; i++) {
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while (!strs[i].startsWith(prefix)) {
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prefix = prefix.slice(0, -1);
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}
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if (prefix === "") {
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return prefix;
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}
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}
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return prefix;
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}
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export function validParentheses(s: string): boolean {
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const bracketsMap: { [key: string]: string } = {
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")": "(",
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"]": "[",
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"}": "{",
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};
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const openBracketsStack = [];
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for (let i = 0; i < s.length; i++) {
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const currentBracket = s[i];
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if (["(", "[", "{"].includes(currentBracket)) {
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openBracketsStack.push(currentBracket);
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} else if (openBracketsStack.pop() !== bracketsMap[currentBracket]) {
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return false;
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}
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}
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return !openBracketsStack.length;
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}
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export function mergeTwoSortedLists(
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list1: ListNode | null,
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list2: ListNode | null,
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): ListNode | null {
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if (list1 === null) return list2;
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if (list2 === null) return list1;
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if (list1.val < list2.val) {
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list1.next = mergeTwoSortedLists(list1.next, list2);
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return list1;
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} else {
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list2.next = mergeTwoSortedLists(list1, list2.next);
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return list2;
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}
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}
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export function removeDuplicatesFromSortedArray(nums: number[]): number {
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let i = 0;
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for (let j = 0; j < nums.length; j++) {
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nums[i++] = nums[j];
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while (j < nums.length - 1 && nums[j] === nums[j + 1]) {
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j++;
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}
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}
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return i;
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}
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export function removeElement(nums: number[], val: number): number {
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let j = 0;
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for (const n of nums) if (n !== val) nums[j++] = n;
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return j;
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}
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168+
export function findTheIndexOfTheFirstOccurrenceInAString(
169+
haystack: string,
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needle: string,
171+
): number {
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let result = -1;
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let matchLoc = 0;
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for (let i = 0; i < haystack.length; i++) {
176+
if (haystack[i] == needle[matchLoc]) {
177+
matchLoc++;
178+
if (needle.length == matchLoc) {
179+
result = i - matchLoc + 1;
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break;
181+
}
182+
} else {
183+
i -= matchLoc;
184+
matchLoc = 0;
185+
}
186+
}
187+
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return result;
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}
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191+
export function searchInsertPosition(nums: number[], target: number): number {
192+
let min = 0;
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let max = nums.length - 1;
194+
195+
while (true) {
196+
const middle = Math.floor((min + max) / 2);
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const num = nums[middle];
198+
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if (max - min <= 1) {
200+
if (target <= nums[min]) {
201+
return min;
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} else if (target <= nums[max]) {
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return max;
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} else {
205+
return max + 1;
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}
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}
208+
209+
if (num > target) {
210+
max = middle;
211+
} else if (num < target) {
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min = middle;
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} else {
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return middle;
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}
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}
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}

‎src/mod.ts

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Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
11
import * as easy from "./easy.ts";
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import * as medium from "./medium.ts";
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import * as hard from "./hard.ts";
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import * as utils from "./utils.ts";
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export { easy, hard, medium };
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export { easy, hard, medium, utils };

‎src/utils.ts

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export class ListNode {
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val: number;
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next: ListNode | null;
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constructor(val?: number, next?: ListNode | null) {
5+
this.val = val === undefined ? 0 : val;
6+
this.next = next === undefined ? null : next;
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}
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}

‎tests/test_easy.ts

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@@ -1,8 +1,100 @@
1-
import { assertArrayIncludes } from "@std/assert";
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import {
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assert,
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assertAlmostEquals,
4+
assertArrayIncludes,
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assertEquals,
6+
assertFalse,
7+
} from "@std/assert";
28
import * as easy from "../src/easy.ts";
9+
import { ListNode } from "../src/utils.ts";
310

411
Deno.test(function twoSumTest() {
512
assertArrayIncludes(easy.twoSum([2, 7, 11, 15], 9), [0, 1]);
613
assertArrayIncludes(easy.twoSum([3, 2, 4], 6), [1, 2]);
714
assertArrayIncludes(easy.twoSum([3, 3], 6), [0, 1]);
815
});
16+
17+
Deno.test(function palindromeNumberTest() {
18+
assert(easy.palindromeNumber(121));
19+
assertFalse(easy.palindromeNumber(-121));
20+
assertFalse(easy.palindromeNumber(10));
21+
});
22+
23+
Deno.test(function romanToIntegerTest() {
24+
assertEquals(easy.romanToInteger("III"), 3);
25+
assertEquals(easy.romanToInteger("LVIII"), 58);
26+
assertEquals(easy.romanToInteger("MCMXCIV"), 1994);
27+
});
28+
29+
Deno.test(function longestCommonPrefixTest() {
30+
assertEquals(easy.longestCommonPrefix(["flower", "flow", "flight"]), "fl");
31+
assertEquals(easy.longestCommonPrefix(["dog", "racecar", "car"]), "");
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});
33+
34+
Deno.test(function validParenthesesTest() {
35+
assert(easy.validParentheses("()"));
36+
assert(easy.validParentheses("()[]{}"));
37+
assertFalse(easy.validParentheses("(]"));
38+
assert(easy.validParentheses("([])"));
39+
});
40+
41+
Deno.test(function mergeTwoSortedListsTest() {
42+
assertEquals(
43+
easy.mergeTwoSortedLists(
44+
new ListNode(1, new ListNode(2, new ListNode(4, null))),
45+
new ListNode(1, new ListNode(3, new ListNode(4))),
46+
),
47+
new ListNode(
48+
1,
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new ListNode(
50+
1,
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new ListNode(
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2,
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new ListNode(3, new ListNode(4, new ListNode(4, null))),
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),
55+
),
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),
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);
58+
assertEquals(easy.mergeTwoSortedLists(null, null), null);
59+
assertEquals(
60+
easy.mergeTwoSortedLists(null, new ListNode(0)),
61+
new ListNode(0),
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);
63+
});
64+
65+
Deno.test(function removeDuplicatesFromSortedArrayTest() {
66+
let nums: number[] = [1, 1, 2];
67+
assertEquals(easy.removeDuplicatesFromSortedArray(nums), 2);
68+
assertEquals(nums.slice(0, 2), [1, 2]);
69+
70+
nums = [0, 0, 1, 1, 1, 2, 2, 3, 3, 4];
71+
assertEquals(easy.removeDuplicatesFromSortedArray(nums), 5);
72+
assertEquals(nums.slice(0, 5), [0, 1, 2, 3, 4]);
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});
74+
75+
Deno.test(function removeElementTest() {
76+
let nums: number[] = [3, 2, 2, 3];
77+
assertEquals(easy.removeElement(nums, 3), 2);
78+
assertArrayIncludes(nums.slice(0, 2), [2, 2]);
79+
80+
nums = [0, 1, 2, 2, 3, 0, 4, 2];
81+
assertEquals(easy.removeElement(nums, 2), 5);
82+
assertArrayIncludes(nums.slice(0, 5), [0, 1, 4, 0, 3])
83+
});
84+
85+
Deno.test(function findTheIndexOfTheFirstOccurrenceInAStringTest() {
86+
assertEquals(
87+
easy.findTheIndexOfTheFirstOccurrenceInAString("sadbutsad", "sad"),
88+
0,
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);
90+
assertEquals(
91+
easy.findTheIndexOfTheFirstOccurrenceInAString("leetcode", "leeto"),
92+
-1,
93+
);
94+
});
95+
96+
Deno.test(function searchInsertPositionTest() {
97+
assertEquals(easy.searchInsertPosition([1, 3, 5, 6], 5), 2);
98+
assertEquals(easy.searchInsertPosition([1, 3, 5, 6], 2), 1);
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assertEquals(easy.searchInsertPosition([1, 3, 5, 6], 7), 4);
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});

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