xuan_abc

摘要： You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you nee 阅读全文

摘要： Given an array of numbers, verify whether it is the correct preorder traversal sequence of a binary search tree. You may assume each number in the seq 阅读全文

摘要： Given a binary tree, return the vertical order traversal of its nodes' values. (ie, from top to bottom, column by column). If two nodes are in the sam 阅读全文

摘要： Given an array A of strings made only from lowercase letters, return a list of all characters that show up in all strings within the list (including d 阅读全文

摘要： We are given two strings, A and B. A shift on A consists of taking string A and moving the leftmost character to the rightmost position. For example, 阅读全文

摘要： Given a complete binary tree, count the number of nodes. Note: Definition of a complete binary tree from Wikipedia:In a complete binary tree every lev 阅读全文

摘要： Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST. Calling next() will return the n 阅读全文

摘要： Given a binary tree where all the right nodes are either leaf nodes with a sibling (a left node that shares the same parent node) or empty, flip it up 阅读全文

摘要： Given an array of n integers nums and a target, find the number of index triplets i, j, k with 0 <= i < j < k < n that satisfy the condition nums[i] + 阅读全文

摘要： Given a binary tree, count the number of uni-value subtrees. A Uni-value subtree means all nodes of the subtree have the same value. Example : Input: 阅读全文