Problem:
Score : 300 points

Problem Statement

We have a grid of H rows and W columns of squares. The color of the square at the i-th row from the top and the j-th column from the left (1 \leq i \leq H, 1 \leq j \leq W) is given to you as a character c_{i,j}: the square is white if c_{i,j} is ., and black if c_{i,j} is #.

Consider doing the following operation:

Choose some number of rows (possibly zero), and some number of columns (possibly zero). Then, paint red all squares in the chosen rows and all squares in the chosen columns.

You are given a positive integer K. How many choices of rows and columns result in exactly K black squares remaining after the operation? Here, we consider two choices different when there is a row or column chosen in only one of those choices.

Constraints

1 \leq H, W \leq 6

1 \leq K \leq HW

c_{i,j} is . or #.

Input

Input is given from Standard Input in the following format:

H W K
c_{1,1}c_{1,2}...c_{1,W}
c_{2,1}c_{2,2}...c_{2,W}
:
c_{H,1}c_{H,2}...c_{H,W}

Output

Print an integer representing the number of choices of rows and columns satisfying the condition.

Sample Input 1

2 3 2
..#
###

Sample Output 1

5

Five choices below satisfy the condition.

The 1-st row and 1-st column

The 1-st row and 2-nd column

The 1-st row and 3-rd column

The 1-st and 2-nd column

The 3-rd column

Sample Input 2

2 3 4
..#
###

Sample Output 2

1

One choice, which is choosing nothing, satisfies the condition.

Sample Input 3

2 2 3
##
##

Sample Output 3

0

Sample Input 4

6 6 8
..##..
.#..#.
#....#
######
#....#
#....#

Sample Output 4

208

Solution in Java (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.*;
import java.math.*;
import java.util.*;
public class Main { 
 
	public static void main(String[] args) { 
		FastScanner I = new FastScanner(); //Input
		OutPut O = new OutPut(); //Output
		int R = I.nextInt();
		int C = I.nextInt();
		int K = I.nextInt();
		int Bl = 0;
		int ans = 0;
		char[][] grid = new char[R][C];
		for (int r = 0; r < R; r++) {
			grid[r] = I.next().toCharArray();
			for (int i = 0; i < C; i++) if (grid[r][i]=='#') Bl++;
		}
		for (int rnum = 0; rnum < (2<<R); rnum++) {
			for (int cnum = 0; cnum < (2<<C); cnum++) {
				boolean[] vis = new boolean[R];
				int cur = 0;
				for (int row = 0; row < R; row++) {
					if ((rnum>>row)%2==1) {
						vis[row]=true;
						for (int c = 0; c < C; c++) {
							if (grid[row][c]=='#') cur++;
						}
					} 
				}
				for (int col = 0; col < C; col++) {
					if ((cnum>>col)%2==1) {
						for (int r = 0; r < R; r++) {
							if (grid[r][col]=='#'&&!vis[r]) {
								cur++;
							}
						}
					} 
				}
				if (cur==Bl-K) ans++;
			}	
		}
		O.pln(ans/4);
	}
	public static ArrayList<String> recur(int N){
		ArrayList<String> ret = new ArrayList<String>();
		if (N==1) {
			for (int i = 0; i <= N; i++) {
				ret.add(Integer.toString(i)+" ");
			}
			return ret;
		}
		ArrayList<String> prev = recur(N-1);
		for (int i = 0; i < prev.size(); i++) {
			String S = prev.get(i);
			String[] cur = prev.get(i).split(" ");
			int cmp = Integer.parseInt(cur[cur.length-1]);
			for (int j = cmp; j <= N; j++) {
				ret.add(S+Integer.toString(j)+" ");
			}
		}
		return ret;
	}
	public static long ceil(long num, long den) {long ans = num/den; if (num%den!=0) 
	ans++; return ans;}
	public static long GCD(long a, long b) {
		if (a==0||b==0) return Math.max(a,b);
		return GCD(Math.min(a, b),Math.max(a, b)%Math.min(a, b));
	}
	public static long FastExp(long base, long exp, long mod) {
		long ans=1;
		while (exp>0) {
			if (exp%2==1) ans*=base;
			exp/=2;
			base*=base;
			base%=mod;
			ans%=mod;
		}
		return ans;
	}
	public static long ModInv(long num,long mod) {return FastExp(num,mod-2,mod);}
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		int nextInt() {return Integer.parseInt(next());}
		long nextLong() {return Long.parseLong(next());};
	}
	static class OutPut{
		PrintWriter w = new PrintWriter(System.out);
		void pln(int x) {w.println(x);w.flush();}
		void pln(long x) {w.println(x);w.flush();}
		void pln(String x) {w.println(x);w.flush();}
		void pln(char x) {w.println(x);w.flush();}
		void pln(StringBuilder x) {w.println(x);w.flush();}
		void p(int x) {w.print(x);w.flush();}
		void p(long x) {w.print(x);w.flush();}
		void p(String x) {w.print(x);w.flush();}
		void p(char x) {w.print(x);w.flush();}
		void p(StringBuilder x) {w.print(x);w.flush();}
	}
}