摘要：
A binary watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom represent the minutes (0-59). Each LED represents 阅读全文
摘要：
Reverse a singly linked list. Hint: A linked list can be reversed either iteratively or recursively. Could you implement both? 迭代。 递归。 阅读全文
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Given an integer array, find three numbers whose product is maximum and output the maximum product. Example 1: Example 2: Note: 将数组按照逆序排序后，如果数组元素都是整数， 阅读全文
摘要：
Given an integer array, find three numbers whose product is maximum and output the maximum product. Example 1: Example 2: Note: 求给定字母组成的最长回文串，使用map记录元 阅读全文
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Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 将一串罗马数字转换为整数，首先使用map建立罗马字母与数字的表示法则。然后从右向左遍 阅读全文
摘要：
Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the arr 阅读全文