Merge branch 'master' of github.com:youngyangyang04/leetcode-master

problems/0005.最长回文子串.md

@@ -288,7 +288,34 @@ class Solution:
         return s[left:right + 1]
 
 ```
+> 双指针法：
+```python
+class Solution:
+    def longestPalindrome(self, s: str) -> str:
+
+        def find_point(i, j, s):
+            while i >= 0 and j < len(s) and s[i] == s[j]:
+                i -= 1
+                j += 1
+            return i + 1, j
 
+        def compare(start, end, left, right):
+            if right - left > end - start:
+                return left, right
+            else:
+                return start, end
+
+        start = 0
+        end = 0
+        for i in range(len(s)):
+            left, right = find_point(i, i, s)
+            start, end = compare(start, end, left, right)
+
+            left, right = find_point(i, i + 1, s)
+            start, end = compare(start, end, left, right)
+        return s[start:end]
+
+```
 ## Go
 
 ```go

problems/0102.二叉树的层序遍历.md

@@ -421,9 +421,10 @@ var levelOrderBottom = function(root) {
             node.left&&queue.push(node.left);
             node.right&&queue.push(node.right);
         }
-        res.push(curLevel);
+	// 从数组前头插入值，避免最后反转数组，减少运算时间
+        res.unshift(curLevel);
     }
-    return res.reverse();
+    return res;
 };
 ```
 
@@ -1263,7 +1264,41 @@ class Solution:
             first = first.left  # 从本层扩展到下一层
         return root
 ```
+JavaScript:
+```javascript
+
+/**
+ * // Definition for a Node.
+ * function Node(val, left, right, next) {
+ *    this.val = val === undefined ? null : val;
+ *    this.left = left === undefined ? null : left;
+ *    this.right = right === undefined ? null : right;
+ *    this.next = next === undefined ? null : next;
+ * };
+ */
+
+/**
+ * @param {Node} root
+ * @return {Node}
+ */
+var connect = function(root) {
+    if (root === null) return root;
+    let queue = [root];
+    while (queue.length) {
+        let n = queue.length;
+        for (let i=0; i<n; i++) {
+            let node = queue.shift();
+            if (i < n-1) {
+                node.next = queue[0];
+            }
+            node.left && queue.push(node.left);
+            node.right && queue.push(node.right);
+        }
+    }
+    return root;
+};
 
+```
 go:
 
 ```GO
@@ -1426,7 +1461,39 @@ class Solution:
             first = dummyHead.next  # 此处为换行操作，更新到下一行
         return root
 ```
+JavaScript:
+```javascript
+/**
+ * // Definition for a Node.
+ * function Node(val, left, right, next) {
+ *    this.val = val === undefined ? null : val;
+ *    this.left = left === undefined ? null : left;
+ *    this.right = right === undefined ? null : right;
+ *    this.next = next === undefined ? null : next;
+ * };
+ */
 
+/**
+ * @param {Node} root
+ * @return {Node}
+ */
+var connect = function(root) {
+    if (root === null) {
+        return null;
+    }
+    let queue = [root];
+    while (queue.length > 0) {
+        let n = queue.length;
+        for (let i=0; i<n; i++) {
+            let node = queue.shift();
+            if (i < n-1) node.next = queue[0];
+            if (node.left != null) queue.push(node.left);
+            if (node.right != null) queue.push(node.right);
+        }
+    }
+    return root;
+};
+```
 go:
 
 ```GO
@@ -1608,6 +1675,36 @@ func maxDepth(root *TreeNode) int {
 
 
 JavaScript：
+```javascript
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var maxDepth = function(root) {
+    // 最大的深度就是二叉树的层数
+    if (root === null) return 0;
+    let queue = [root];
+    let height = 0;
+    while (queue.length) {
+        let n = queue.length;
+        height++;
+        for (let i=0; i<n; i++) {
+            let node = queue.shift();
+            node.left && queue.push(node.left);
+            node.right && queue.push(node.right);
+        }
+    }
+    return height;
+};
+```
 
 # 111.二叉树的最小深度
 
@@ -1746,9 +1843,40 @@ func minDepth(root *TreeNode) int {
 }
 ```
 
-
-
 JavaScript：
+```javascript
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var minDepth = function(root) {
+    if (root === null) return 0;
+    let queue = [root];
+    let deepth = 0;
+    while (queue.length) {
+        let n = queue.length;
+        deepth++;
+        for (let i=0; i<n; i++) {
+            let node = queue.shift();
+            // 如果左右节点都是null，则该节点深度最小
+            if (node.left === null && node.right === null) {
+                return deepth;
+            }
+            node.left && queue.push(node.left);;
+            node.right && queue.push (node.right);
+        }
+    }
+    return deepth;
+};
+```
 
 
 

problems/0491.递增子序列.md

@@ -313,7 +313,72 @@ var findSubsequences = function(nums) {
 
 ```
 
+C:
+```c
+int* path;
+int pathTop;
+int** ans;
+int ansTop;
+int* length;
+//将当前path中的内容复制到ans中
+void copy() {
+    int* tempPath = (int*)malloc(sizeof(int) * pathTop);
+    memcpy(tempPath, path, pathTop * sizeof(int));
+    length[ansTop] = pathTop;
+    ans[ansTop++] = tempPath;
+}
+
+//查找uset中是否存在值为key的元素
+int find(int* uset, int usetSize, int key) {
+    int i;
+    for(i = 0; i < usetSize; i++) {
+        if(uset[i] == key)
+            return 1;
+    }
+    return 0;
+}
+
+void backTracking(int* nums, int numsSize, int startIndex) {
+    //当path中元素大于1个时，将path拷贝到ans中
+    if(pathTop > 1) {
+        copy();
+    }
+    int* uset = (int*)malloc(sizeof(int) * numsSize);
+    int usetTop = 0;
+    int i;
+    for(i = startIndex; i < numsSize; i++) {
+        //若当前元素小于path中最后一位元素 || 在树的同一层找到了相同的元素，则continue
+        if((pathTop > 0 && nums[i] < path[pathTop - 1]) || find(uset, usetTop, nums[i]))
+            continue;
+        //将当前元素放入uset
+        uset[usetTop++] = nums[i];
+        //将当前元素放入path
+        path[pathTop++] = nums[i];
+        backTracking(nums, numsSize, i + 1);
+        //回溯
+        pathTop--;
+    }
+}
 
+int** findSubsequences(int* nums, int numsSize, int* returnSize, int** returnColumnSizes){
+    //辅助数组初始化
+    path = (int*)malloc(sizeof(int) * numsSize);
+    ans = (int**)malloc(sizeof(int*) * 33000);
+    length = (int*)malloc(sizeof(int*) * 33000);
+    pathTop = ansTop = 0;
+
+    backTracking(nums, numsSize, 0);
+
+    //设置数组中返回元素个数，以及每个一维数组的长度
+    *returnSize = ansTop;
+    *returnColumnSizes = (int*)malloc(sizeof(int) * ansTop);
+    int i;
+    for(i = 0; i < ansTop; i++) {
+        (*returnColumnSizes)[i] = length[i];
+    }
+    return ans;
+}
+```
 
 
 -----------------------

problems/0617.合并二叉树.md

@@ -507,6 +507,8 @@ func mergeTrees(root1 *TreeNode, root2 *TreeNode) *TreeNode {
 
 ## JavaScript 
 
+> 递归法：
+
 ```javascript
 /**
  * Definition for a binary tree node.
@@ -535,6 +537,53 @@ var mergeTrees = function (root1, root2) {
     return preOrder(root1, root2);
 };
 ```
+> 迭代法：
+
+```javascript
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root1
+ * @param {TreeNode} root2
+ * @return {TreeNode}
+ */
+var mergeTrees = function(root1, root2) {
+    if (root1 === null) return root2;
+    if (root2 === null) return root1;
+
+    let queue = [];
+    queue.push(root1);
+    queue.push(root2);
+    while (queue.length) {
+        let node1 = queue.shift();
+        let node2 = queue.shift();;
+        node1.val += node2.val;
+        if (node1.left !== null && node2.left !== null) {
+            queue.push(node1.left);
+            queue.push(node2.left);
+        }
+        if (node1.right !== null && node2.right !== null) {
+            queue.push(node1.right);
+            queue.push(node2.right);
+        }
+        if (node1.left === null && node2.left !== null) {
+            node1.left = node2.left;
+        }
+        if (node1.right === null && node2.right !== null) {
+            node1.right = node2.right;
+        } 
+    }
+    return root1;
+};
+
+```
 
 
 -----------------------

problems/0704.二分查找.md

@@ -288,15 +288,16 @@ func search(nums []int, target int) int {
  * @param {number} target
  * @return {number}
  */
+/**
 var search = function(nums, target) {
-    let left = 0, right = nums.length;
-    // 使用左闭右开区间 [left, right)
-    while (left < right) {
+    let left = 0, right = nums.length - 1;
+    // 使用左闭右闭区间
+    while (left <= right) {
         let mid = left + Math.floor((right - left)/2);
         if (nums[mid] > target) {
-            right = mid;  // 去左区间寻找
+            right = mid - 1;  // 去左面闭区间寻找
         } else if (nums[mid] < target) {
-            left = mid + 1;   // 去右区间寻找
+            left = mid + 1;   // 去右面闭区间寻找
         } else {
             return mid;
         }