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Happy Number Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any po 阅读全文
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Count of Smaller Numbers After Self You are given an integer array nums and you have to return a new counts array. The counts array has the property w 阅读全文
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Patching Array Given a sorted positive integer array nums and an integer n, add/patch elements to the array such that any number in range [1, n] inclu 阅读全文
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Self Crossing You are given an array x of n positive numbers. You start at point (0,0) and moves x[0] metres to the north, then x[1] metres to the wes 阅读全文
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Increasing Triplet Subsequence Given an unsorted array return whether an increasing subsequence of length 3 exists or not in the array. Formally the f 阅读全文
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Reconstruct Itinerary Given a list of airline tickets represented by pairs of departure and arrival airports [from, to], reconstruct the itinerary in 阅读全文
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Verify Preorder Serialization of a Binary Tree One way to serialize a binary tree is to use pre-order traversal. When we encounter a non-null node, we 阅读全文
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Odd Even Linked List Given a singly linked list, group all odd nodes together followed by the even nodes. Please note here we are talking about the no 阅读全文
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Power of Three Given an integer, write a function to determine if it is a power of three. Follow up:Could you do it without using any loop / recursion 阅读全文
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Longest Increasing Path in a Matrix Given an integer matrix, find the length of the longest increasing path. From each cell, you can either move to fo 阅读全文