摘要：
Follow up for N-Queens problem. Now, instead outputting board configurations, return the total number of distinct solutions. 题意：仅要求给出解的种数。 思路：这题是n que 阅读全文
摘要：
The n-queens puzzle is the problem of placing n queens on an n×nchessboard such that no two queens attack each other. Given an integer n, return all d 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. click to show follow up. Follow up: Did you use extra sp 阅读全文
摘要：
Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that: For example, Give 阅读全文