摘要： Implement pow(x, n), which calculates x raised to the power n(xn). Example 1: Example 2: Example 3: Note: -100.0 < x < 100.0 n is a 32-bit signed inte 阅读全文

摘要： Given a collection of numbers that might contain duplicates, return all possible unique permutations. Example: 有重复数字的情况，之前在Subsets II，我们采取的是在某一个递归内，用f 阅读全文

摘要： Given a collection of distinct integers, return all possible permutations. Example: 规律：类似插入排序，每个数都有多个可插入的位置。 递归的时候：循环插入的位置。递归结束条件：插入到最后一个数。 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 two non-negative integers num1 and num2represented as strings, return the product of num1 and num2, also represented as a string. Example 1: Exa 阅读全文