Merge pull request #116 from gyt95/js_chapter_computational_complexity

Add JS for chapter of computational complexity
This commit is contained in:
Yudong Jin 2022-12-16 20:48:00 +08:00 committed by GitHub
commit 2f14d71c11
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
2 changed files with 68 additions and 2 deletions

View file

@ -0,0 +1,43 @@
/**
* File: leetcode_two_sum.js
* Created Time: 2022-12-15
* Author: gyt95 (gytkwan@gmail.com)
*/
function twoSumBruteForce(nums, target) {
const n = nums.length;
// 两层循环,时间复杂度 O(n^2)
for (let i = 0; i < n; i++) {
for (let j = i + 1; j < n; j++) {
if (nums[i] + nums[j] === target) {
return [i, j];
}
}
}
return [];
}
function twoSumHashTable(nums, target) {
// 辅助哈希表,空间复杂度 O(n)
let m = {};
// 单层循环,时间复杂度 O(n)
for (let i = 0; i < nums.length; i++) {
if (m[nums[i]] !== undefined) {
return [m[nums[i]], i];
} else {
m[target - nums[i]] = i;
}
}
return [];
}
/* Driver Code */
// 方法一
const nums = [2, 7, 11, 15], target = 9;
let res = twoSumBruteForce(nums, target);
console.log("方法一 res = ", res);
// 方法二
res = twoSumHashTable(nums, target);
console.log("方法二 res = ", res);

View file

@ -90,7 +90,18 @@ comments: true
=== "JavaScript" === "JavaScript"
```js title="leetcode_two_sum.js" ```js title="leetcode_two_sum.js"
function twoSumBruteForce(nums, target) {
const n = nums.length;
// 两层循环,时间复杂度 O(n^2)
for (let i = 0; i < n; i++) {
for (let j = i + 1; j < n; j++) {
if (nums[i] + nums[j] === target) {
return [i, j];
}
}
}
return [];
}
``` ```
=== "TypeScript" === "TypeScript"
@ -204,7 +215,19 @@ comments: true
=== "JavaScript" === "JavaScript"
```js title="leetcode_two_sum.js" ```js title="leetcode_two_sum.js"
function twoSumHashTable(nums, target) {
// 辅助哈希表,空间复杂度 O(n)
let m = {};
// 单层循环,时间复杂度 O(n)
for (let i = 0; i < nums.length; i++) {
if (m[nums[i]] !== undefined) {
return [m[nums[i]], i];
} else {
m[target - nums[i]] = i;
}
}
return [];
}
``` ```
=== "TypeScript" === "TypeScript"