xuan_abc

摘要： Implement the following operations of a stack using queues. push(x) -- Push element x onto stack. pop() -- Removes the element on top of the stack. to 阅读全文

摘要： Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue. pop() -- Removes the element from in front 阅读全文

摘要： Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) -- Push element x onto stack. pop() -- Remov 阅读全文

摘要： You are given a perfect binary tree where all leaves are on the same level, and every parent has two children. The binary tree has the following defin 阅读全文

摘要： Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, /. Each operand may be an integer or another e 阅读全文

摘要： Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example, 阅读全文

摘要： Convert a BST to a sorted circular doubly-linked list in-place. Think of the left and right pointers as synonymous to the previous and next pointers i 阅读全文

摘要： You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping yo 阅读全文

摘要： Given a binary tree, flatten it to a linked list in-place. For example, given the following tree: 1 / \ 2 5 / \ \ 3 4 6 The flattened tree should look 阅读全文

摘要： Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at most one transaction 阅读全文