feat: 新增算法和promise文章总结

Author: zjgyb

docs/views/algorithm/2022-04-08.md

@@ -11,6 +11,170 @@ tags:
 
 之前的[算法打卡](https://zjgyb.github.io/views/algorithm/2021-5-30.html)已经快一年了，由于代码行数较多，因此打开缓慢，故决定再新建一个，用于下一周期的算法打卡
 
+## 【字符串】检查相同字母间的距离
+[地址](https://leetcode.cn/problems/check-distances-between-same-letters/)
+
+```ts
+function checkDistances(s: string, distance: number[]): boolean {
+    const map = new Map()
+    for (let i = 0; i < s.length; i++) {
+        if (map.has(s[i])) {
+            const index = s[i].charCodeAt(0) - 'a'.charCodeAt(0)
+            if (distance[index] !== i - map.get(s[i]) - 1) {
+                return false
+            }
+        } else {
+            map.set(s[i], i)
+        }
+    }
+
+    return true
+};
+```
+
+## 【双指针】最长优雅子数组
+[地址](https://leetcode.cn/problems/longest-nice-subarray/)
+
+```ts
+function longestNiceSubarray(nums: number[]): number {
+   const len = nums.length
+    if (len === 1) {
+        return 1
+    }
+
+    let prev = 0
+    let next = 1
+    let result = 0
+
+    while (next < len) {
+        // 确定新加入的是否与之前的&为0
+        let i = next - 1
+        while(i >= prev) {
+            if ((nums[i] & nums[next]) !== 0) {
+                prev = i + 1
+                break
+            }
+            i--
+        }
+        result = Math.max(result, next - prev + 1)
+        next++
+    }
+    return result
+};
+```
+
+## 【链表】奇偶链表
+[地址](https://leetcode.cn/problems/odd-even-linked-list/)
+
+```ts
+// 大致思路
+// 比如1->2->3->4->5->6->7
+// 第一步2->3互换，然后变成1->3->2->4->5->6->7
+// 第二步2->4与5互换，变成1->3->5->2->4->6->7
+// 第三步2->4->6与7互换，变成1->3->5->7->2->4->6
+function oddEvenList(head: ListNode | null): ListNode | null {
+    let node = head
+    let index = 1
+
+    while(node) {
+        let j = index
+        let next = node
+        while (j > 0) {
+            next = next.next
+            j--
+        }
+
+        if (!next) {
+            break
+        }
+
+        let afterNext = next.next
+        if (!afterNext) {
+            break
+        }
+
+        next.next = next.next.next
+        afterNext.next = null
+        next = node.next
+        node.next = afterNext
+        node.next.next = next
+        node = node.next
+        index++
+    }
+
+    return head
+};
+```
+
+```ts
+// 一个取奇数链表
+// 一个取偶数链表
+function oddEvenList(head: ListNode | null): ListNode | null {
+    if (!head) {
+        return head
+    }
+    let evenNode = head
+    let oddNode = head.next
+
+    let evenList = evenNode
+    let oddList = oddNode
+    let node = head.next
+    let index = 0
+
+    while(node) {
+        if (index % 2) {
+            oddList.next = node.next
+            oddList = oddList.next
+        } else {
+            evenList.next = node.next
+            if (node.next) {
+                evenList = evenList.next
+            }
+        }
+        node = node.next
+        index++
+    }
+    evenList.next = oddNode
+    return evenNode
+};
+```
+
+## LRU 缓存
+[地址](https://leetcode.cn/problems/lru-cache/)
+
+```ts
+class LRUCache {
+    max: number
+    cache: Map<number, number>
+
+    constructor(capacity: number) {
+        this.max = capacity
+        this.cache = new Map()
+    }
+
+    get(key: number): number {
+        if (this.cache.has(key)) {
+            const val = this.cache.get(key)
+            this.cache.delete(key)
+            this.cache.set(key, val)
+        }
+        return this.cache.get(key) ?? -1
+    }
+
+    put(key: number, value: number): void {
+        this.cache.delete(key)
+        this.cache.set(key, value)
+
+        if (this.cache.size > this.max) {
+            for (const key of this.cache.keys()) {
+                this.cache.delete(key)
+                break
+            }
+        }
+    }
+}
+```
+
 ## 【链表】重排链表
 [地址](https://leetcode.cn/problems/reorder-list/)
 

docs/views/js/2022/2022-03-15.md

@@ -1,6 +1,77 @@
 ---
-title: Promise总结
+title: Promise专题
 date: 2022-08-29
 categories: JavaScript
 ---
 
+## 特点
+
+1. 有三种状态，分别为 `pending`、`fulfilled`、`reject`，其他操作无法改变
+2. 状态只能从`pending`到`fulfilled`或`reject`
+
+## 优、缺点
+
+优点：
+1. 以同步的流程表达出来，避免了回调函数的层层嵌套
+
+缺点：
+1. 无法取消
+2. 内部抛出的错误无法反应到外部
+3. 处于`pending`状态无法知道处于哪一个状态
+
+## 注意点
+
+1. 在`new Promise`中如果没有使用`resolve`或`reject`，那么promise的状态一直在`pending`
+2. `catch`存在跳过的现象
+3. 返回一个非Promise的值会被`Promise.resolve`包裹
+4. 不能返回自身否则会报错
+5. 传入非函数会发生值渗透
+
+```ts
+Promise.resolve(1).then(2).then(Promise.resolve(3)).then(console.log) // 1
+```
+
+## 手写Promise相关方法
+
+### Promise.all
+
+```ts
+if (!Promise.all) {
+    Promise.all = (arr: unknown[]) => {
+        return new Promise((resolve, reject) => {
+            const result: Promise<unknown>[] = []
+            const getResult = (index: number, value) => {
+                result[index] = value
+
+                if (result.length === arr.length) {
+                    resolve(result)
+                }
+            }
+            for (let i = 0; i < arr.length; i++) {
+                Promise.resolve(arr[i]).then((value) => {
+                    getResult(i, value)
+                }, reject)
+            }
+        })
+    }
+}
+```
+
+### Promise.race
+
+```ts
+if (!Promise.race1) {
+    Promise.race1 = (arr: Promise<unknown>[]) => {
+        return new Promise((resolve, reject) => {
+            for (let i = 0; i < arr.length; i++) {
+                Promise.resolve(arr[i]).then(resolve, reject)
+            }
+        })
+    }
+}
+```
+
+## 参考文章
+
+- [掘金](https://juejin.cn/post/6844904077537574919)
+- [阮一峰](https://es6.ruanyifeng.com/#docs/promise#Promise-%E7%9A%84%E5%90%AB%E4%B9%89)