0

# Minimum Height Trees

Minimum Height TreesFor a undirected graph with tree characteristics, we can choose any node as the root. The result graph is then a rooted tree. Among all possible rooted trees, those with minimum h

0

# Perfect Squares

Perfect SquaresGiven a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, …) which sum to n. For example:123Given n = 12, return 3 because 12 = 4 + 4 + 4;G

0

# Course Schedule II

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

0

# Course Schedule

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

0

# Number of Islands

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

0

# Binary Tree Right Side View

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

0

# Binary Tree Zigzag Level Order Traversal

Binary Tree Zigzag Level Order TraversalGiven a binary tree, return the zigzag level order traversal of its nodes’ values. (ie, from left to right, then right to left for the next level and alternate

0

# Minimum Depth of Binary Tree

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

0

# Binary Tree Level Order Traversal II

Binary Tree Level Order Traversal IIGiven a binary tree, return the bottom-up level order traversal of its nodes’ values. (ie, from left to right, level by level from leaf to root). For example:Given

0

# Binary Tree Level Order Traversal

Binary Tree Level Order TraversalGiven a binary tree, return the level order traversal of its nodes’ values. (ie, from left to right, level by level). For example:Given binary tree [3,9,20,null,null,

0

# Symmetric Tree

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 / \ /