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Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the or 阅读全文
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Given a binary tree, return the tilt of the whole tree. The tilt of a tree node is defined as the absolute difference between the sum of all left subt 阅读全文
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For a web developer, it is very important to know how to design a web page's size. So, given a specific rectangular web page’s area, your job by now i 阅读全文
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Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number. The function 阅读全文
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Given a Binary Search Tree and a target number, return true if there exist two elements in the BST such that their sum is equal to the given target. E 阅读全文
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Given a word, you need to judge whether the usage of capitals in it is right or not. We define the usage of capitals in a word to be right when one of 阅读全文
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Given an integer array with no duplicates. A maximum tree building on this array is defined as follow: Construct the maximum tree by the given array a 阅读全文
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Given two strings representing two complex numbers. You need to return a string representing their multiplication. Note i2 = -1 according to the defin 阅读全文
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Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements that appear twi 阅读全文
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Given a binary tree, find the leftmost value in the last row of the tree. Example 1: Example 2: 阅读全文
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Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and r 阅读全文
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Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all 阅读全文
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Given two non-empty binary trees s and t, check whether tree t has exactly the same structure and node values with a subtree of s. A subtree of s is a 阅读全文
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Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longestpath betwee 阅读全文
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Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements of [1, n] 阅读全文
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You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water. Grid cells are connected horizontally/ve 阅读全文
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You need to construct a string consists of parenthesis and integers from a binary tree with the preorder traversing way. The null node needs to be rep 阅读全文
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Given a group of two strings, you need to find the longest uncommon subsequence of this group of two strings. The longest uncommon subsequence is defi 阅读全文
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Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Outp 阅读全文
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In MATLAB, there is a very useful function called 'reshape', which can reshape a matrix into a new one with different size but keep its original data. 阅读全文
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Given an integer array with even length, where different numbers in this array represent different kinds of candies. Each number means one candy of th 阅读全文
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Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are n 阅读全文
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Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of 阅读全文
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Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. E 阅读全文
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You are given a list of non-negative integers, a1, a2, ..., an, and a target, S. Now you have 2 symbols + and -. For each integer, you should choose o 阅读全文