随笔分类 - Leetcode
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 to
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摘要：Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. For this problem, a height-balanced bina
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摘要：Given a binary tree, return all root-to-leaf paths. Note: A leaf is a node with no children. Example: Approach #1: C++. [recursive] Approach #2: Java.
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摘要：The thief has found himself a new place for his thievery again. There is only one entrance to this area, called the "root." Besides the root, each hou
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摘要：Given a list of airline tickets represented by pairs of departure and arrival airports [from, to], reconstruct the itinerary in order. All of the tick
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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：Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. Example
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摘要：Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 whic
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摘要：Given a non-empty binary tree, find the maximum path sum. For this problem, a path is defined as any sequence of nodes from some starting node to any
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摘要：Given a binary tree, flatten it to a linked list in-place. For example, given the following tree: The flattened tree should look like: Approach #1: C+
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摘要：Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. Note: A leaf is a node with no children. Exampl
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摘要：Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest l
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摘要：Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Example 1: Input: [1,3,null,null,2
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摘要：955. Delete Columns to Make Sorted II We are given an array A of N lowercase letter strings, all of the same length. Now, we may choose any set of del
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摘要：Given an integer n, generate all structurally unique BST's (binary search trees) that store values 1 ... n. Example: Input: 3 Output: [ [1,null,3,2],
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摘要：Given the root node of a binary search tree, return the sum of values of all nodes with value between L and R (inclusive). The binary search tree is g
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摘要：Given a Binary Search Tree (BST) with the root node root, return the minimum difference between the values of any two different nodes in the tree. Exa
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摘要：Implement a MyCalendarThree class to store your events. A new event can always be added. Your class will have one method, book(int start, int end). Fo
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摘要：Implement a MyCalendarTwo class to store your events. A new event can be added if adding the event will not cause a triple booking. Your class will ha
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