随笔分类 - Great Questions
摘要：Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors. OJ's undirected graph serialization: Nodes are labeled
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摘要：Design a data structure that supports all following operations in O(1) time. insert(val): Inserts an item val to the set if not already present.remove
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摘要：Given an array which consists of non-negative integers and an integer m, you can split the array into m non-empty continuous subarrays. Write an algor
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摘要：Convert a Binary Search Tree to a sorted Circular Doubly-Linked List in place. You can think of the left and right pointers as synonymous to the prede
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摘要：A frog is crossing a river. The river is divided into x units and at each unit there may or may not exist a stone. The frog can jump on a stone, but i
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摘要：Given an integer matrix, find the length of the longest increasing path. From each cell, you can either move to four directions: left, right, up or do
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摘要：Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results. Note: The input string may cont
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摘要：Closest Binary Search Tree Value Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target. Not
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摘要：There 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 t
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摘要：You are given a m x n 2D grid initialized with these three possible values. -1 - A wall or an obstacle. 0 - A gate. INF - Infinity means an empty room
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摘要：Given a binary tree, find the largest subtree which is a Binary Search Tree (BST), where largest means subtree with largest number of nodes in it. Not
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摘要：For 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 roote
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摘要：Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may comple
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摘要：According to the Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John
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摘要：Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If the fractional part is repeating
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摘要：The API: int read4(char *buf) reads 4 characters at a time from a file. The return value is the actual number of characters read. For example, it retu
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摘要：You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices of substring(s) in s that is a conca
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摘要：Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n. For example:Given n = 13,Return
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摘要：Given a binary search tree and a node in it, find the in-order successor of that node in the BST. 1 public class Solution { 2 3 public TreeNode inorde
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摘要：Range Sum Query 2D - Mutable Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1)
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