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…

hadoop集群性能低下的常见原因 (一)硬件环境 1.CPU/内存不足,或未充分利用 2.网络原因 3.磁盘原因 (二)map任务原因 1.输入文件中小文件过多,导致多次启动和停止JVM进程.可以设置JVM重用. 2.数据倾斜:大文件且不可分割,导致处理这些文件的map需要很长时间. 3.数据本地化效果差. (三)reduce任务的原因 1.reduce任务数量过大或过小 2.数据倾斜:一部分key的记录数量太大,导致某些reduce执行过慢 3.缓慢的shuffle和排序 (四)hadoop…

人见人爱A-B Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 53836    Accepted Submission(s): 15147 Problem Description 参加过上个月月赛的同学一定还记得其中的一个最简单的题目,就是{A}+{B},那个题目求的是两个集合的并集,今天我们这个A-B求的是两个集合的差,就是做集合的…

Uncle Tom's Inherited Land* Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 1869    Accepted Submission(s): 777 Special Judge Problem Description Your old uncle Tom inherited a piece of land fr…

Largest Rectangle in a Histogram Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 11706    Accepted Submission(s): 3219 Problem Description A histogram is a polygon composed of a sequence of rec…

#include <cstdio> #include <iostream> #include <cstring> #include<queue> #include<cmath> using namespace std; const int INF = 0x3fffffff; int g[1005][1005]; int pre[1005]; int m; int bfs(int s,int t) { queue<int>q; q.pu…

胜利大逃亡(续) Time Limit : 4000/2000ms (Java/Other)   Memory Limit : 65536/32768K (Java/Other) Total Submission(s) : 22   Accepted Submission(s) : 10 Font: Times New Roman | Verdana | Georgia Font Size: ← → Problem Description Ignatius再次被魔王抓走了(搞不懂他咋这么讨魔王喜…

Tempter of the Bone Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 70032    Accepted Submission(s): 19286 Problem Description The doggie found a bone in an ancient maze, which fascinated him a…

FatMouse' Trade Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 42953    Accepted Submission(s): 14336 Problem Description FatMouse prepared M pounds of cat food, ready to trade with the cats g…

Drainage Ditches Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 8861    Accepted Submission(s): 4141 Problem Description Every time it rains on Farmer John's fields, a pond forms over Bessie's…