Commit 8d2c896

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✨ next premutation

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Lines changed: 23 additions & 16 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,24 +1,31 @@`
`1`		`-// HELP:`
`2`		`-import { ListNode } from '../_utils';`
`3`		`-`
`4`		`-export const addTwoNumbers = (l1, l2) => {`
`5`		`- const dummyHead = new ListNode(0);`
`6`		`- let curr = dummyHead;`
	`1`	`+/**`
	`2`	`+ * Definition for singly-linked list.`
	`3`	`+ * function ListNode(val) {`
	`4`	`+ * this.val = val;`
	`5`	`+ * this.next = null;`
	`6`	`+ * }`
	`7`	`+ */`
	`8`	`+/**`
	`9`	`+ * @param {ListNode} l1`
	`10`	`+ * @param {ListNode} l2`
	`11`	`+ * @return {ListNode}`
	`12`	`+ */`
	`13`	`+var addTwoNumbers = function (l1, l2) {`
	`14`	`+ const node = new ListNode();`
	`15`	`+ let cur = node;`
`7`	`16`	`let carry = 0;`
`8`	`17`
`9`	`18`	`while (l1 \|\| l2) {`
`10`		`- let x = l1 ? l1.val : 0;`
`11`		`- let y = l2 ? l2.val : 0;`
`12`		`- let sum = carry + x + y;`
`13`		`- if (l1) l1 = l1.next;`
`14`		`- if (l2) l2 = l2.next;`
	`19`	`+ const sum = (l1 ? l1.val : 0) + (l2 ? l2.val : 0) + carry;`
	`20`	`+ carry = sum >= 10 ? 1 : 0;`
	`21`	`+ cur.next = new ListNode(sum % 10);`
	`22`	`+ cur = cur.next;`
`15`	`23`
`16`		`- carry = ~~(sum / 10);`
`17`		`- curr.next = new ListNode(sum % 10);`
`18`		`- curr = curr.next;`
	`24`	`+ l1 && (l1 = l1.next);`
	`25`	`+ l2 && (l2 = l2.next);`
`19`	`26`	`}`
`20`	`27`
`21`		`- if(carry >0)curr.next = new ListNode(carry);`
	`28`	`+ carry &&(cur.next = new ListNode(carry));`
`22`	`29`
`23`		`- return dummyHead.next;`
	`30`	`+ return node.next;`
`24`	`31`	`};`

Lines changed: 16 additions & 12 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,16 +1,20 @@`
`1`		`-// TODO:`
`2`		`-export function lengthOfLongestSubstring(str) {`
`3`		`- const strLength = str.length;`
`4`		`- let maxLength = 0;`
	`1`	`+/**`
	`2`	`+ * @param {string} s`
	`3`	`+ * @return {number}`
	`4`	`+ */`
	`5`	`+var lengthOfLongestSubstring = function (s) {`
	`6`	`+ const len = s.length;`
`5`	`7`	`const map = new Map();`
`6`		`- let i = 0;`
`7`		`- for (let j = 0; j < strLength; j++) {`
`8`		`- if (map.has(str.charAt(j))) {`
`9`		`- i = Math.max(map.get(str.charAt(j)), i);`
	`8`	`+ let start = 0;`
	`9`	`+ let res = 0;`
	`10`	`+`
	`11`	`+ for (let end = 0; end < len; end++) {`
	`12`	`+ if (map.has(s[end])) {`
	`13`	`+ start = Math.max(map.get(s[end]), start);`
`10`	`14`	`}`
`11`		`- maxLength = Math.max(maxLength,j - i + 1);`
`12`		`- map.set(str.charAt(j),j + 1);`
	`15`	`+ res = Math.max(res,end - start + 1);`
	`16`	`+ map.set(s[end],end + 1);`
`13`	`17`	`}`
`14`	`18`
`15`		`- return maxLength;`
`16`		`-}`
	`19`	`+ return res;`
	`20`	`+};`

Lines changed: 38 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,38 @@`
	`1`	`+const assert = require('assert').strict;`
	`2`	`+`
	`3`	`+function nextPermutation(nums) {`
	`4`	`+ let i = nums.length - 2; // 向左遍历,i从倒数第二开始是为了nums[i+1]要存在`
	`5`	`+`
	`6`	`+ // 寻找第一个小于右邻居的数`
	`7`	`+ while (i >= 0 && nums[i] >= nums[i + 1]) {`
	`8`	`+ i--;`
	`9`	`+ }`
	`10`	`+`
	`11`	`+ // 这个数在数组中存在,从它身后挑一个数,和它换`
	`12`	`+ if (i >= 0) {`
	`13`	`+ let j = nums.length - 1; // 从最后一项,向左遍历`
	`14`	`+`
	`15`	`+ // 寻找第一个大于 nums[i] 的数`
	`16`	`+ while (j >= 0 && nums[j] <= nums[i]) {`
	`17`	`+ j--;`
	`18`	`+ }`
	`19`	`+`
	`20`	`+ [nums[i], nums[j]] = [nums[j], nums[i]]; // 两数交换,实现变大`
	`21`	`+ }`
	`22`	`+`
	`23`	`+ // 如果 i = -1,说明是递减排列,如 3 2 1,没有下一排列,直接翻转为最小排列:1 2 3`
	`24`	`+ let l = i + 1;`
	`25`	`+ let r = nums.length - 1;`
	`26`	`+ while (l < r) {`
	`27`	`+ // i 右边的数进行翻转,使得变大的幅度小一些`
	`28`	`+ [nums[l], nums[r]] = [nums[r], nums[l]];`
	`29`	`+ l++;`
	`30`	`+ r--;`
	`31`	`+ }`
	`32`	`+`
	`33`	`+ return nums;`
	`34`	`+}`
	`35`	`+`
	`36`	`+assert.deepEqual(nextPermutation([1, 2, 3]), [1, 3, 2]);`
	`37`	`+assert.deepEqual(nextPermutation([3, 2, 1]), [1, 2, 3]);`
	`38`	`+assert.deepEqual(nextPermutation([1, 1, 5]), [1, 5, 1]);`

Lines changed: 9 additions & 10 deletions

Original file line number	Diff line number	Diff line change
`@@ -3,22 +3,21 @@`
`3`	`3`	`* @return {string}`
`4`	`4`	`*/`
`5`	`5`
`6`		`-// 字节跳动`
`7`		`-// HELP:`
`8`		`-`
`9`		`-var longestPalindrome = function(s) {`
	`6`	`+var longestPalindrome = function (s) {`
`10`	`7`	`let n = s.length;`
`11`		`- let res = "";`
`12`		`- let dp = Array.from(new Array(n), () => new Array(n).fill(0));`
	`8`	`+ let dp = Array.from({ length: n }, () => Array(n).fill(false));`
	`9`	`+ let start = 0;`
	`10`	`+ let end = 0;`
`13`	`11`
`14`	`12`	`for (let i = n - 1; i >= 0; i--) {`
`15`	`13`	`for (let j = i; j < n; j++) {`
`16`		`- dp[i][j] = s[i] == s[j] && (j - i < 2 \|\| dp[i + 1][j - 1]);`
`17`		`- if (dp[i][j] && j - i + 1 > res.length) {`
`18`		`- res = s.slice(i, j + 1);`
	`14`	`+ dp[i][j] = s[i] === s[j] && (j - i < 2 \|\| dp[i + 1][j - 1]);`
	`15`	`+ if (dp[i][j] && j - i > end - start) {`
	`16`	`+ start = i;`
	`17`	`+ end = j;`
`19`	`18`	`}`
`20`	`19`	`}`
`21`	`20`	`}`
`22`	`21`
`23`		`- return res;`
	`22`	`+ return s.slice(start,end+1);`
`24`	`23`	`};`

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