feat: add javaScript solutions for lcof problems

Author: matteokjh

lcof/面试题03. 数组中重复的数字/README.md

@@ -59,6 +59,21 @@ class Solution {
 }
 ```
 
+### JavaScript
+```js
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var findRepeatNumber = function(nums) {
+    let m = {}
+    for(let num of nums) {
+        if(m[num]) return num
+        m[num] = 1
+    }
+};
+```
+
 ### ...
 ```
 

lcof/面试题03. 数组中重复的数字/Solution.js

@@ -0,0 +1,11 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var findRepeatNumber = function(nums) {
+    let m = {}
+    for(let num of nums) {
+        if(m[num]) return num
+        m[num] = 1
+    }
+};

lcof/面试题04. 二维数组中的查找/README.md

@@ -73,6 +73,31 @@ class Solution {
 }
 ```
 
+### JavaScript
+```js
+/**
+ * @param {number[][]} matrix
+ * @param {number} target
+ * @return {boolean}
+ */
+var findNumberIn2DArray = function(matrix, target) {
+    let row = matrix.length
+    let col = matrix[0].length
+    function dfs(i,j) {
+        if(i < 0 || j >= col) {
+            return false
+        }
+        if(matrix[i][j] === target) return true
+        else if(matrix[i][j] > target) {
+            return dfs(i-1,j)
+        } else {
+            return dfs(i,j+1)
+        }
+    }
+    return dfs(row-1,0)
+};
+```
+
 ### ...
 ```
 

lcof/面试题04. 二维数组中的查找/Solution.js

@@ -0,0 +1,21 @@
+/**
+ * @param {number[][]} matrix
+ * @param {number} target
+ * @return {boolean}
+ */
+var findNumberIn2DArray = function(matrix, target) {
+    let row = matrix.length
+    let col = matrix[0].length
+    function dfs(i,j) {
+        if(i < 0 || j >= col) {
+            return false
+        }
+        if(matrix[i][j] === target) return true
+        else if(matrix[i][j] > target) {
+            return dfs(i-1,j)
+        } else {
+            return dfs(i,j+1)
+        }
+    }
+    return dfs(row-1,0)
+};

lcof/面试题05. 替换空格/README.md

@@ -33,6 +33,17 @@ class Solution {
 }
 ```
 
+### JavaScript
+```js
+/**
+ * @param {string} s
+ * @return {string}
+ */
+var replaceSpace = function(s) {
+    return s.split(' ').join('%20')
+};
+```
+
 ### ...
 ```
 

lcof/面试题05. 替换空格/Solution.js

@@ -0,0 +1,7 @@
+/**
+ * @param {string} s
+ * @return {string}
+ */
+var replaceSpace = function(s) {
+    return s.split(' ').join('%20')
+};

lcof/面试题06. 从尾到头打印链表/README.md

@@ -60,6 +60,11 @@ class Solution {
 }
 ```
 
+### JavaScript
+```js
+
+```
+
 ### ...
 ```
 

lcof/面试题06. 从尾到头打印链表/Solution.js

@@ -0,0 +1,20 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @return {number[]}
+ */
+var reversePrint = function(head) {
+    let node = head
+    let res = []
+    while(node) {
+        res.unshift(node.val)
+        node = node.next
+    }
+    return res
+};

lcof/面试题07. 重建二叉树/README.md

@@ -99,6 +99,43 @@ class Solution {
 }
 ```
 
+### JavaScript
+```js
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {number[]} preorder
+ * @param {number[]} inorder
+ * @return {TreeNode}
+ */
+var buildTree = function(preorder, inorder) {
+    if(!preorder || !preorder.length) return null
+    let preIdx = 0
+    let inMap = {}
+    for(let i=0;i<inorder.length;i++) {
+        inMap[inorder[i]] = i
+    }
+    function func(start, end) {
+        if(start > end) {
+            return null
+        }
+        let preVal = preorder[preIdx]
+        preIdx++
+        let inIdx = inMap[preVal]
+        let node = new TreeNode(preVal)
+        node.left = func(start, inIdx - 1)
+        node.right = func(inIdx + 1, end)
+        return node
+    }
+    return func(0, preorder.length - 1)
+};
+```
+
 ### ...
 ```
 

lcof/面试题07. 重建二叉树/Solution.js

@@ -0,0 +1,33 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {number[]} preorder
+ * @param {number[]} inorder
+ * @return {TreeNode}
+ */
+var buildTree = function(preorder, inorder) {
+    if(!preorder || !preorder.length) return null
+    let preIdx = 0
+    let inMap = {}
+    for(let i=0;i<inorder.length;i++) {
+        inMap[inorder[i]] = i
+    }
+    function func(start, end) {
+        if(start > end) {
+            return null
+        }
+        let preVal = preorder[preIdx]
+        preIdx++
+        let inIdx = inMap[preVal]
+        let node = new TreeNode(preVal)
+        node.left = func(start, inIdx - 1)
+        node.right = func(inIdx + 1, end)
+        return node
+    }
+    return func(0, preorder.length - 1)
+};

lcof/面试题09. 用两个栈实现队列/README.md

@@ -92,6 +92,38 @@ class CQueue {
  */
 ```
 
+### JavaScript
+```js
+var CQueue = function() {
+    this.data = []
+    this.helper = []
+};
+/** 
+ * @param {number} value
+ * @return {void}
+ */
+CQueue.prototype.appendTail = function(value) {
+    this.data.push(value)
+};
+/**
+ * @return {number}
+ */
+CQueue.prototype.deleteHead = function() {
+    if(this.data.length) {
+        while(this.data.length > 1) {
+            this.helper.push(this.data.pop())
+        }
+        let res = this.data.pop()
+        while(this.helper.length) {
+            this.data.push(this.helper.pop())
+        }
+        return res
+    } else {
+        return -1
+    }
+};
+```
+
 ### ...
 ```
 

lcof/面试题09. 用两个栈实现队列/Solution.js

@@ -0,0 +1,28 @@
+var CQueue = function() {
+    this.data = []
+    this.helper = []
+};
+/** 
+ * @param {number} value
+ * @return {void}
+ */
+CQueue.prototype.appendTail = function(value) {
+    this.data.push(value)
+};
+/**
+ * @return {number}
+ */
+CQueue.prototype.deleteHead = function() {
+    if(this.data.length) {
+        while(this.data.length > 1) {
+            this.helper.push(this.data.pop())
+        }
+        let res = this.data.pop()
+        while(this.helper.length) {
+            this.data.push(this.helper.pop())
+        }
+        return res
+    } else {
+        return -1
+    }
+};

lcof/面试题10- I. 斐波那契数列/README.md

@@ -58,6 +58,25 @@ class Solution {
 }
 ```
 
+### JavaScript
+```js
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var fib = function(n) {
+    if(!n) return 0
+    let pre = 0
+    let cur = 1
+    for(let i=2;i<=n;i++) {
+        let c = (pre + cur)%(1e9+7)
+        pre = cur
+        cur = c
+    }
+    return cur
+};
+```
+
 ### ...
 ```
 

lcof/面试题10- I. 斐波那契数列/Solution.js

@@ -0,0 +1,15 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var fib = function(n) {
+    if(!n) return 0
+    let pre = 0
+    let cur = 1
+    for(let i=2;i<=n;i++) {
+        let c = (pre + cur)%(1e9+7)
+        pre = cur
+        cur = c
+    }
+    return cur
+};

lcof/面试题10- II. 青蛙跳台阶问题/README.md

@@ -53,6 +53,25 @@ class Solution {
 }
 ```
 
+### JavaScript
+```js
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var numWays = function(n) {
+    if(!n) return 1
+    let pre = 1
+    let cur = 1
+    for(let i=2;i<=n;i++) {
+        let c = (pre + cur) % (1e9 + 7)
+        pre = cur
+        cur = c
+    }
+    return cur
+};
+```
+
 ### ...
 ```
 

lcof/面试题10- II. 青蛙跳台阶问题/Solution.js

@@ -0,0 +1,15 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var numWays = function(n) {
+    if(!n) return 1
+    let pre = 1
+    let cur = 1
+    for(let i=2;i<=n;i++) {
+        let c = (pre + cur) % (1e9 + 7)
+        pre = cur
+        cur = c
+    }
+    return cur
+};