题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5988 题目大意: 给定n个点,m条有向边,每个点是一个吃饭的地方,每个人一盒饭.每个点有S个人,有B盒饭.每条边只能被走c次,每条边上都有电线,第一个人通过的时候,不会破坏电线,从第二个人开始,每次都有概率p破坏掉电线.使得每个人都能吃饭,求最小破坏电线的概率. 解题思路: 题目要求我们求最小破坏电线的概率,就是一个最小乘积问题,加上log可以将其转变为加法,那样就可以使用费用刘来解决了. 按以下方…

Coding Contest Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 1751    Accepted Submission(s): 374 Problem Description A coding contest will be held in this university, in a huge playground. The…

http://acm.split.hdu.edu.cn/showproblem.php?pid=5988 题意:在acm比赛的时候有多个桌子,桌子与桌子之间都有线路相连,每个桌子上会有一些人和一些食物,现在要吃午饭了,有些人就可能需要到别的桌子去拿食物,但是必须沿着线路走,每根线路第一个人走时没事,接下来的人走时会有一定概率使网络瘫痪,并且每根线路最多可以走c人.现在问使网络瘫痪的最低概率是多少? 思路:建立费用流,由于概率是要相乘,这里可以转换成log后进行计算,最后再转换回来即可. 由于这题…

Problem DescriptionA coding contest will be held in this university, in a huge playground. The whole playground would be divided into N blocks, and there would be M directed paths linking these blocks. The i-th path goes from the ui-th block to the v…

Coding Contest http://acm.hdu.edu.cn/showproblem.php?pid=5988 Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 5337    Accepted Submission(s): 1256 Problem Description A coding contest will be he…

题目链接: Coding Contest Time Limit: 2000/1000 MS (Java/Others)     Memory Limit: 65536/65536 K (Java/Others) Problem Description A coding contest will be held in this university, in a huge playground. The whole playground would be divided into N blocks,…

Coding Contest Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 5968    Accepted Submission(s): 1413 Problem Description A coding contest will be held in this university, in a huge playground. Th…

HDU5988 题意: 有n个区域,每个区域有s个人,b份饭.现在告诉你每个区域间的有向路径,每条路有容量和损坏路径的概率.问如何走可以使得路径不被破坏的概率最小.第一个人走某条道路是百分百不会损坏道路的. 思路: 对于每个人,他从起点到目的地,不损坏道路的概率是(1 - p[1]*p[2]...*p[r]).相乘不好做,对减号右边的乘法取对数,就成了相加,就可以愉快的做相加运算了,就是可以跑费用流了.这道题spfa还有加入esp=1e-8. //#pragma GCC optimize(3)…

Problem Description A coding contest will be held in this university, in a huge playground. The whole playground would be divided into N blocks, and there would be M directed paths linking these blocks. The i-th path goes from the u_i-th block to the…

2016青岛现场赛的一题,由于第一次走过不会产生影响,需要拆点,不过比赛时没想到,此外还有许多细节要注意,如要加eps,时间卡得较紧要注意细节优化等 #include <iostream> #include <cstring> #include <queue> #include <cstdio> #include <cmath> #include <cstdlib> #include <algorithm> #includ…