Codeforces Round 411 (Div. 1)
F
Fake bullions
Codeforces
3400
原题
← E→
翻译中…

In Isart people don't die. There are $*n*$ gangs of criminals. The $*i*$-th gang contains $*s*_{*i*}$ evil people numerated from $0$ to $*s*_{*i*} - 1$. Some of these people took part in a big mine robbery and picked one gold bullion each (these people are given in the input). That happened $10^{100}$ years ago and then all of the gangs escaped to a remote area, far from towns.

翻译中…

During the years, they were copying some gold bullions according to an organized plan in order to not get arrested. They constructed a tournament directed graph (a graph where there is exactly one directed edge between every pair of vertices) of gangs (the graph is given in the input). In this graph an edge from $*u*$ to $*v*$ means that in the $*i*$-th hour the person image of the gang $*u*$ can send a fake gold bullion to person image of gang $*v*$. He sends it if he has some bullion (real or fake), while the receiver doesn't have any. Thus, at any moment each of the gangsters has zero or one gold bullion. Some of them have real bullions, and some of them have fake ones.

翻译中…

In the beginning of this year, the police has finally found the gangs, but they couldn't catch them, as usual. The police decided to open a jewelry store so that the gangsters would sell the bullions. Thus, every gangster that has a bullion (fake or real) will try to sell it. If he has a real gold bullion, he sells it without problems, but if he has a fake one, there is a choice of two events that can happen:

翻译中…
  • The person sells the gold bullion successfully.
  • The person is arrested by police.
翻译中…

The power of a gang is the number of people in it that successfully sold their bullion. After all selling is done, the police arrests $*b*$ gangs out of top gangs. Sort the gangs by powers, we call the first $*a*$ gang top gangs(you can sort the equal powers in each order). Consider all possible results of selling fake gold bullions and all possible choice of $*b*$ gangs among the top gangs. Count the number of different sets of these $*b*$ gangs modulo $10^{9} + 7$. Two sets $*X*$ and $*Y*$ are considered different if some gang is in $*X*$ and isn't in $*Y*$.

翻译中…

Input

翻译中…

The first line contains four integers $*n*$, $*a*$ and $*b*$ ($1 ≤ *b* ≤ *a* ≤ *n* ≤ 5·10^{3}$) — the number of gangs, the constants $*a*$ and $*b*$ from the statement.

翻译中…

Then $*n*$ lines follow, each line contains a string of size $*n*$ consisting of zeros and ones. The $*j*$-th character in the $*i*$-th of these lines is equal to $1$, then the vertex $*i*$ have a directed edge to the vertex $*j*$. It is guaranteed that $*a*_{*ii*} = 0$ and $*a*_{*ij*} + *a*_{*ji*} = 1$ if $*i* ≠ *j*$.

翻译中…

Then $*n*$ lines follow, each line starts with the integer $*s*_{*i*}$ ($1 ≤ *s*_{*i*} ≤ 2·10^{6}$) — the number of gangsters in the $*i*$-th gang, and then contains a string of zeros and ones with length $*s*_{*i*}$. The $*j*$-th character is $0$ if the $*j*$-th person of the $*i*$-th gang had a real gold bullion initially, otherwise it is $1$. It is guaranteed that the sum of $*s*_{*i*}$ does not exceed $2·10^{6}$.

翻译中…

Output

翻译中…

Print single integer: the number of different sets of $*b*$ gangs the police can arrest modulo $10^{9} + 7$.

翻译中…

样例

Input #1
2 2 1
01
00
5 11000
6 100000
Output #1
2
InputCopy OutputCopy
Input #2
5 2 1
00000
10000
11011
11000
11010
2 00
1 1
6 100110
1 0
1 0
Output #2
5
InputCopy OutputCopy
题目信息
题号
804F
时间限制
3 s
内存限制
512 MB
标签
组合数学
DFS 及类似
动态规划
图论
数论

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。