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问题描述：Givenn, how many structurally uniqueBST's(binary search trees) that store values 1...n?For example,Givenn= 3, there are a total of 5 unique BST's... 阅读全文
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问题描述Given a binary tree, return thepreordertraversal of its nodes' values.For example:Given binary tree{1,#,2,3}, 1 \ 2 / 3return[1,2,3]... 阅读全文
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问题描述：Given a sorted array, remove the duplicates in place such that each element appear onlyonceand return the new length.Do not allocate extra space ... 阅读全文
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问题描述：Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the t... 阅读全文
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问题描述Given a linked list, return the node where the cycle begins. If there is no cycle, returnnull.Follow up:Can you solve it without using extra space... 阅读全文