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…

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…

Danganronpa 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5835 Description Chisa Yukizome works as a teacher in the school. She prepares many gifts, which consist of n kinds with a[i] quantities of each kind, for her students and wants to hold a cl…

Ball 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5821 Description ZZX has a sequence of boxes numbered 1,2,...,n. Each box can contain at most one ball. You are given the initial configuration of the balls. For 1≤i≤n, if the i-th box is empty the…

题目传送门:http://acm.hdu.edu.cn/showproblem.php?pid=4004 题目意思是青蛙要过河,现在给你河的宽度,河中石头的个数(青蛙要从石头上跳过河,这些石头都是在垂直于河岸的一条直线上) 还有青蛙能够跳跃的 最多 的次数,还有每个石头离河岸的距离,问的是青蛙一步最少要跳多少米可以过河> 这是一道二分加贪心的题,从0到的河宽度开始二分,二分出一个数然后判断在这样的最小步数(一步跳多少距离)下能否过河 判断的时候要贪心 主要难在思维上,关键是要想到二分上去,能想到…

Saving HDU Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 4638    Accepted Submission(s): 2111 Problem Description 话说上回讲到海东集团面临内外交困,公司的元老也只剩下XHD夫妇二人了.显然,作为多年拼搏的商人,XHD不会坐以待毙的.   一天,当他正在苦思冥想解困良策…