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摘要： Given a linked list, return the node where the cycle begins. If there is no cycle, return `null`. 阅读全文

摘要： Given a **non-empty** string *s* and a dictionary *wordDict* containing a list of **non-empty** words, determine if *s* can be segmented into a space-separated sequence of one or more dictionary words. 阅读全文

摘要： Given a binary tree, flatten it to a linked list in-place. 阅读全文

摘要： Given a binary tree, determine if it is a valid binary search tree (BST). 阅读全文

摘要： Given *n*, how many structurally unique **BST's** (binary search trees) that store values 1 ... *n*? 阅读全文

摘要： Given a binary tree, return the *inorder* traversal of its nodes' values. 阅读全文

摘要： Given a set of **distinct** integers, *nums*, return all possible subsets (the power set). 阅读全文

摘要： Given an array with *n* objects colored red, white or blue, sort them **in-place** so that objects of the same color are adjacent, with the colors in the order red, white and blue. 阅读全文

摘要： Given a *m* x *n* grid filled with non-negative numbers, find a path from top left to bottom right which *minimizes* the sum of all numbers along its path. 阅读全文

摘要： A robot is located at the top-left corner of a *m* x *n* grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below). How many possible unique paths are there? 阅读全文