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Problem : Given a non empty list of words, return the k most frequent elements. Your answer should be sorted by frequency from highest to lowest. If t 阅读全文
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Problem : Give a string s, count the number of non empty (contiguous) substrings that have the same number of 0's and 1's, and all the 0's and all the 阅读全文
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Problem : Given a non empty array of non negative integers nums, the degree of this array is defined as the maximum frequency of any one of its elemen 阅读全文
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Problem : On an NxN chessboard, a knight starts at the r th row and c th column and attempts to make exactly K moves. The rows and columns are 0 index 阅读全文
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Problem : There is a robot starting at position (0, 0), the origin, on a 2D plane. Given a sequence of its moves, judge if this robot ends up at (0, 0 阅读全文
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Problem : Given a non negative integer, you could swap two digits at most once to get the maximum valued number. Return the maximum valued number you 阅读全文
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Problem : Given an unsorted array of integers, find the length of longest continuous increasing subsequence (subarray). Example 1: Example 2: Note: Le 阅读全文
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Problem : You're now a baseball game point recorder. Given a list of strings, each string can be one of the 4 following types: 1. Integer (one round's 阅读全文
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Problem : Initially on a notepad only one character 'A' is present. You can perform two operations on this notepad for each step: 1. Copy All: You can 阅读全文
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Problem : You are given n pairs of numbers. In every pair, the first number is always smaller than the second number. Now, we define a pair (c, d) can 阅读全文