摘要： Given a linked list, remove the nth node from the end of list and return its head. For example, Given linked list: 1->2->3->4->5, and n = 2. After rem 阅读全文

摘要： Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telepho 阅读全文

摘要： Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 普及一下罗马计数法 The base I - 1 V - 5 X - 10 L - 阅读全文

摘要： Implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of the preceding elemen 阅读全文

摘要： Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below 阅读全文

摘要： You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single 阅读全文

摘要： Implement pow(x, n). 这题主要考察分治法，这样效率就可达到O(logn) 需要注意的是：n>0时 n为偶数时 xn = xn/2 * xn/2，n为奇数时 xn = x(n-1)/2 * x(n-1)/2 * x n=0时 ，xn = 1 n<0时 xn = 1 / x-n 代码 阅读全文

摘要： Implement strStr(). Returns a pointer to the first occurrence of needle in haystack, or null if needle is not part of haystack. 方法一：暴力破解，O(mn)，超时，写了这段 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： Implement int sqrt(int x). Compute and return the square root of x. 传说中的牛顿法，请查看百度百科 某人说我偷懒，那我就决定还是翻些资料出来比较好。。。 牛顿法主要用于两方面，一是求方程根，二是最优化处理。 求方程根的原理是利用泰勒 阅读全文