for the backtracking part, thanks to the video of stanford cs106b lecture 10 by Julie Zelenski for the nice explanation of recursion and backtracking, highly recommended. in hdu 2553 cout N-Queens solutions problem, dfs is used. // please ignore, bel…

use fgets, and remove the potential '\n' in the string's last postion. (main point) remove redundancy there must be a stack, at first sight, you need a stack of type myNode, but think deeper, matrix multiplication is valid only if A.c=B.r, then the n…

Description 上次Gardon的迷宫城堡小希玩了很久(见Problem B),现在她也想设计一个迷宫让Gardon来走.但是她设计迷宫的思路不一样,首先她认为所有的通道都应该是双向连通的,就是说如果有一个通道连通了房间A和B,那么既可以通过它从房间A走到房间B,也可以通过它从房间B走到房间A,为了提高难度,小希希望任意两个房间有且仅有一条路径可以相通(除非走了回头路).小希现在把她的设计图给你,让你帮忙判断她的设计图是否符合她的设计思路.比如下面的例子,前两个是符合条件的,但是最后一个…

one recursive approach to solve hdu 1016, list all permutations, solve N-Queens puzzle. reference: the video of stanford cs106b lecture 10 by Julie Zelenski https://www.youtube.com/watch?v=NdF1QDTRkck // hdu 1016, 795MS #include <cstdio> #include &l…

If you understand the comments below, never will you make mistakes with binary search! thanks to A simple CPP solution with lower_bound and C++ O(logn) Binary Search that handles duplicate, thanks to phu1ku 's answer on the second post. http://en.cpp…

huffman coding, greedy algorithm. std::priority_queue, std::partition, when i use the three commented lines, excution time increase to 15ms from 0ms, due to worse locality? thanks to http://acm.hdu.edu.cn/discuss/problem/post/reply.php?action=support…

thanks to http://acm.hdu.edu.cn/discuss/problem/post/reply.php?action=support&postid=19638&messageid=1&deep=0 for the test case provided. below is an excerpt data 8 11 9 8 8 8 4 3 2 11 8 8 8 8 4 3 2 answer 800 #include <cstdio> #include…

thanks to http://stackoverflow.com/questions/2144459/using-scanf-to-accept-user-input and http://stackoverflow.com/questions/456303/how-to-validate-input-using-scanf for the i/o part. thanks to http://www.haodaima.net/art/137347 for the rounding part…

A simple problem Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 3702 Accepted Submission(s): 1383 Problem Description Zty很痴迷数学问题..一天,yifenfei出了个数学题想难倒他,让他回答1 / n.但Zty却回答不了^_^. 请大家编程帮助他. Input 第一行…

RGCDQ Time Limit:3000MS Memory Limit:65536KB 64bit IO Format:%I64d & %I64u Submit Status Practice HDU 5317 Appoint description: Description Mr. Hdu is interested in Greatest Common Divisor (GCD). He wants to find more and more interesting things abou…