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摘要： Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. Given a string containing just 阅读全文

摘要： Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Given a string, find the first non 阅读全文

摘要： Given an integer, convert it to a roman numeral. The number is guaranteed to be within the range from 1 to 3999. Given an integer, convert it to a rom 阅读全文

摘要： Given a roman numeral, convert it to an integer. The answer is guaranteed to be within the range from 1 to 3999. Given a roman numeral, convert it to 阅读全文

摘要： Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maxim 阅读全文

摘要： Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maxim 阅读全文

摘要： Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place. Given a m x n matrix, if an element is 0, set its entire 阅读全文

摘要： Suppose you are at a party with n people (labeled from 0 to n - 1) and among them, there may exist one celebrity. The definition of a celebrity is tha 阅读全文

摘要： Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.) You have 阅读全文

摘要： Given two strings S and T, determine if they are both one edit distance apart. There are three types of edits that can be performed on strings: insert 阅读全文