[Usaco2016 Dec]Robotic Cow Herd

时间限制:10s      空间限制:128MB

题目描述

Bessie is hoping to fool Farmer John by building a herd of KK realistic robotic cows (1≤K≤100,000)
.It turns out that building a robotic cow is somewhat complicated. There are N (1≤n≤100,000) indiv
idual locations on the robot into which microcontrollers must be connected (so a single microcontrol
ler must be connected at each location). For each of these locations, Bessie can select from a numbe
r of different models of microcontroller, each varying in cost.For the herd of robotic cows to look 
convincing to Farmer John, no two robots should behave identically. Therefore, no two robots should 
have exactly the same set of microcontrollers. For any pair of robots, there should be at least one 
location at which the two robots use a different microcontroller model. It is guaranteed that there 
will always be enough different microcontroller models to satisfy this constraint.Bessie wants to ma
ke her robotic herd as cheaply as possible. Help her determine the minimum possible cost to do this!
贝茜想制造K(1 ≤ K ≤ 100,000)个奶牛机器人来玩弄农夫约翰。一个奶牛机器人需要在N个位置分别安装一个控
制器。每个位置有M_i(1 ≤ M_i ≤ 10)种控制器可供选择,并且每种控制器都有自己价值P_{i,j}(1 ≤ P_{i,j} 
≤ 100,000,000)。为了使得奶牛机器人看起来像真的一样,因此贝茜要求没有两个机器人拥有完全相同的控制器
——也就是说至少有一个位置选择了不同的控制器。数据保证在这种条件下至少有K种不同的奶牛。请帮助贝茜计
算制造K个这样的机器人的最小花费。


输入格式

The first line of input contains NN and KK separated by a space.
The following N lines contain a description of the different microcontroller models available for ea
ch location. The iith such line starts with MiMi (1≤Mi≤10), giving the number of models available 
for location ii. This is followed by MiMi space separated integers Pi,jPi,j giving the costs of thes
e different models (1≤Pi,j≤100,000,000).


输出格式

Output a single line, giving the minimum cost to construct K robots.


样例输入

3 10
4 1 5 3 10
3 2 3 3
5 1 3 4 6 6

样例输出

61

提示

没有写明提示


题目来源

Platinum 鸣谢Firstlast提供译文