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charlespunk / [LeetCode] Unique Binary Search Trees II

Created September 9, 2013 05:42

	Given n, generate all structurally unique BST's (binary search trees) that store values 1...n.

	For example,
	Given n = 3, your program should return all 5 unique BST's shown below.

	1 3 3 2 1
	\ / / / \ \
	3 2 1 1 3 2
	/ / \ \
	2 1 2 3

charlespunk / [LeetCode] Unique Binary Search Trees

Last active December 22, 2015 13:49

	Given n, how many structurally unique BST's (binary search trees) that store values 1...n?

	For example,
	Given n = 3, there are a total of 5 unique BST's.

	1 3 3 2 1
	\ / / / \ \
	3 2 1 1 3 2
	/ / \ \
	2 1 2 3

charlespunk / [LeetCode] Interleaving String

Created September 8, 2013 03:32

	Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.

	For example,
	Given:
	s1 = "aabcc",
	s2 = "dbbca",

	When s3 = "aadbbcbcac", return true.
	When s3 = "aadbbbaccc", return false.

charlespunk / [LeetCode] Recover Binary Search Tree

Created September 2, 2013 19:28

	Two elements of a binary search tree (BST) are swapped by mistake.

	Recover the tree without changing its structure.

	Note:
	A solution using O(n) space is pretty straight forward. Could you devise a constant space solution?

charlespunk / [LeetCode] Binary Tree Inorder Traversal

Created September 2, 2013 19:05

	Given a binary tree, return the inorder traversal of its nodes' values.

	For example:
	Given binary tree {1,#,2,3},

	1
	\
	2
	/
	3

charlespunk / [LeetCode] Validate Binary Search Tree

Created September 2, 2013 18:35

	Given 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 than the node's key.
	The right subtree of a node contains only nodes with keys greater than the node's key.
	Both the left and right subtrees must also be binary search trees.

charlespunk / [LeetCode] Same Tree

Created September 2, 2013 18:28

	Given two binary trees, write a function to check if they are equal or not.

	Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

charlespunk / [LeetCode] Symmetric Tree

Created September 2, 2013 18:19

	Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).

	For example, this binary tree is symmetric:

	1
	/ \
	2 2
	/ \ / \
	3 4 4 3
	But the following is not:

charlespunk / [LeetCode] Binary Tree Zigzag Level Order Traversal

Created September 2, 2013 03:00

	Given 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 between).

	For example:
	Given binary tree {3,9,20,#,#,15,7},

	3
	/ \
	9 20
	/ \
	15 7

charlespunk / [LeetCode] Maximum Depth of Binary Tree

Created September 1, 2013 17:38

	Given 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.