Merge branch 'master' of https://github.com/sl1673495/leetcode-javascript

Author: sl1673495

二叉树/107. 二叉树的层次遍历 II.js

@@ -0,0 +1,40 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+
+let TreeNode = require('../工具/二叉树.js')
+
+/**
+ * @param {TreeNode} root
+ * @return {number[][]}
+ */
+var levelOrderBottom = function (root) {
+  let res = []
+  let dfs = (node, level = 0) => {
+      if (!node) return
+
+      if (!res[level]) {
+          res[level] = []
+      }
+
+      dfs(node.left, level + 1)
+      dfs(node.right, level + 1)
+
+      res[level].push(node.val)
+  }
+
+  dfs(root)
+  return res.reverse()
+};
+
+var t = new TreeNode(3)
+t.left = new TreeNode(9)
+t.right = new TreeNode(20)
+t.right.left = new TreeNode(15)
+t.right.right = new TreeNode(7)
+
+console.log(levelOrderBottom(t))

动态规划/22.括号生成.js

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+let generateParenthesis = function (n) {
+  let dp = []
+  dp[0] = ['']
+  dp[1] = ['()']
+
+  for (let i = 2; i <= n; i++) {
+      let res = []
+      for (let j = 0; j <= i - 1; j++) {
+           let inners = dp[j]
+           let outers = dp[i - 1 - j]
+
+           for (let inner of inners) {
+               for (let outer of outers) {
+                   res.push(`(${inner})${outer}`)
+               }
+           }
+      }
+      dp[i] = res
+  }
+  return dp[n]
+};
+
+console.log(generateParenthesis(4))