这种样式的最优解问题一看就是贪心.如果一下不好看,那么可以按照由特殊到一般的思维方式,先看n==2时怎么选顺序(这种由特殊到一般的思维方式是思考很多问题的入口): 有两个队时,若先选第一个,则ans=a1+a2+b2*a1;若先选第二个,则ans=a2+a1+b1*a2;所以选择顺序就比b2*a1和b1*a2就好了. 那么当有n>2个队时,能不能也这么搞?当然可以,每次剩下那几个队没选,我就两两比,两两之间比较时,之前用的时间都要加上是和顺序无关的,顺序影响的只是b2*a1和b1*a2而已(如果…

HDU 4442 Physical Examination(贪心) 题目链接http://acm.split.hdu.edu.cn/showproblem.php?pid=4442 Description WANGPENG is a freshman. He is requested to have a physical examination when entering the university. Now WANGPENG arrives at the hospital. Er-.. Th…

Physical Examination Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 6155 Accepted Submission(s): 1754 Problem Description WANGPENG is a freshman. He is requested to have a physical examination wh…

Physical Examination Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u Submit Status Practice HDU 4442 Description WANGPENG is a freshman. He is requested to have a physical examination when entering the university. Now WAN…

这个题目用贪心来做,关键是怎么贪心最小,那就是排序的问题了. 加入给定两个数a1, b1, a2, b2.那么如果先选1再选2的话,总的耗费就是a1 + a1 * b2 + a2; 如果先选2再选1,总的耗费就是a2 + a2 * b1 + a1.这时比较两个数的大小,发现两边都有a1+a2,所以只是比较a1*b2和a2 * b1的大小. #include <cstdio> #include <cstring> #include <algorithm> using na…

昨天模拟赛的时候坑了好久,刚开始感觉是dp,仔细一看数据范围太大. 题目大意:一个人要参加考试,一共有n个科目,每个科目都有一个相应的队列,完成这门科目的总时间为a+b*(前面已完成科目所花的总时间).问:怎样安排考试的顺序使考完所花的总时间最短. 分析:假设已经花了time时间,在剩下的科目中任意取两个科目x,y. 先考试x:Tx=time+(ay*time+ax+bx*by*(ax+time)): 先考试y:Ty=time+(by*time+bx+ax+ay*(bx+time)). 化简之后…

Draw Something http://acm.hdu.edu.cn/showproblem.php?pid=4450 o(n)统计输入每个数的平方和. #include<cstdio> int main(){ int n,x; while(~scanf("%d",&n),n){ ; while(n--){ scanf("%d",&x); ans+=x*x; } printf("%d\n",ans); } ; }…

Walking Race   Description flymouse's sister wc is very capable at sports and her favorite event is walking race. Chasing after the championship in an important competition, she comes to a training center to attend a training course. The center has N…

现象:在windows XP x64下,使用用户安装的msxml6库加载xml文件时失败. 进一步说明: 该xml文档使用了W3C的名称空间 xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance"默认的名称空间是 "urn:hl7-org:v3", Schema 验证文档为 "urn:hl7-org:v3 CDA.xsd". 在这个文档中使用了属性 xsi: type="CD&quo…

Walking Race Time Limit: 10000MS   Memory Limit: 131072K Total Submissions: 5409   Accepted: 1371 Case Time Limit: 3000MS Description flymouse’s sister wc is very capable at sports and her favorite event is walking race. Chasing after the championshi…