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Given two integersnandk, return all possible combinations ofknumbers out of 1 ...n.For example,Ifn= 4 andk= 2, a solution is:[ [2,4], [3,4], [2,3],... 阅读全文
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Given a binary tree, determine if it is height-balanced.For this problem, a height-balanced binary tree is defined as a binary tree in which the depth... 阅读全文
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Follow up for "Remove Duplicates":What if duplicates are allowed at mosttwice?For example,Given sorted array A =[1,1,1,2,2,3],Your function should ret... 阅读全文
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Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest le... 阅读全文
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Reverse a linked list from positionmton. Do it in-place and in one-pass.For example:Given1->2->3->4->5->NULL,m= 2 andn= 4,return1->4->3->2->5->NULL.No... 阅读全文
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Write an efficient algorithm that searches for a value in anmxnmatrix. This matrix has the following properties:Integers in each row are sorted from l... 阅读全文
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Two elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Note:A solution using O(n) space is ... 阅读全文
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Given a binary tree, return thebottom-up level ordertraversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For exa... 阅读全文
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Suppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e.,0 1 2 4 5 6 7might become4 5 6 7 0 1 2).You are given a target value t... 阅读全文
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There are N gas stations along a circular route, where the amount of gas at station i is gas[i].You have a car with an unlimited gas tank and it costs... 阅读全文