House Robber IIIThe thief has found himself a new place for his thievery again. There is only one entrance to this area, called the “root.” Besides the root, each house has one and only one parent ho
Reconstruct ItineraryGiven a list of airline tickets represented by pairs of departure and arrival airports [from, to], reconstruct the itinerary in order. All of the tickets belong to a man who depa
Course Schedule IIThere are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is
Course ScheduleThere are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is ex
Number of IslandsGiven a 2d grid map of ‘1’s (land) and ‘0’s (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertical
Binary Tree Right Side ViewGiven a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. For example:Given the followi
Sum Root to Leaf NumbersGiven a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 which represents the nu
Flatten Binary Tree to Linked ListGiven a binary tree, flatten it to a linked list in-place. For example:Given 12345 1 / \ 2 5 / \ \3 4 6 The flattened tree should look like: 1234567891
Path Sum IIGiven a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum. For example:Given the below binary tree and sum = 22, 1234567 5 / \ 4 8
Convert Sorted List to Binary Search TreeGiven a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. 提示 解題應用 DepthFirstSearch InorderTravel
Convert Sorted Array to Binary Search TreeGiven an array where elements are sorted in ascending order, convert it to a height balanced BST. 提示 解題應用 DepthFirstSearch InorderTravel Default:12
Construct Binary Tree from Inorder and Postorder TraversalGiven inorder and postorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree.
Construct Binary Tree from Preorder and Inorder TraversalGiven preorder and inorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. 提
Validate Binary Search TreeGiven a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less
Binary Tree PathsGiven a binary tree, return all root-to-leaf paths. For example, given the following binary tree: 12345 1 / \2 3 \ 5 All root-to-leaf paths are: 1["1->2->5",
Minimum Depth of Binary TreeGiven a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 提示 解題應用
Balanced Binary TreeGiven a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of ever
Maximum Depth of Binary TreeGiven a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. 提示 解題應用
Symmetric TreeGiven a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is symmetric: 12345 1 / \ 2 2 / \ /