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Start from integer 1, remove any integer that contains 9 such as 9, 19, 29... So now, you will have a new integer sequence: 1, 2, 3, 4, 5, 6, 7, 8, 10 阅读全文
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Given a string s. An awesome substring is a non-empty substring of s such that we can make any number of swaps in order to make it palindrome. Return 阅读全文
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There are G people in a gang, and a list of various crimes they could commit. The i-th crime generates a profit[i] and requires group[i] gang members 阅读全文
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Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n. Example: Input: 13 Output: 6 Exp 阅读全文
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Given a m x n binary matrix mat. In one step, you can choose one cell and flip it and all the four neighbours of it if they exist (Flip is changing 1 阅读全文
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Given an array of positive integers target and an array initial of same size with all zeros. Return the minimum number of operations to form a target 阅读全文
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Given the root of a binary tree and an integer distance. A pair of two different leaf nodes of a binary tree is said to be good if the length of the s 阅读全文
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Given a positive integer N, how many ways can we write it as a sum of consecutive positive integers? Example 1: Input: 5 Output: 2 Explanation: 5 = 5 阅读全文
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Given an array of words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justif 阅读全文
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Given a string s of lowercase letters, you need to find the maximum number of non-empty substrings of s that meet the following conditions: The substr 阅读全文