Problem:
Score : 200 points

Problem Statement

There is a grid of squares with H horizontal rows and W vertical columns.
The square at the i-th row from the top and the j-th column from the left is represented as (i, j).
Each square is black or white.
The color of the square is given as an H-by-W matrix (a_{i, j}).
If a_{i, j} is ., the square (i, j) is white; if a_{i, j} is #, the square (i, j) is black.

Snuke is compressing this grid.
He will do so by repeatedly performing the following operation while there is a row or column that consists only of white squares:

Operation: choose any one row or column that consists only of white squares, remove it and delete the space between the rows or columns.

It can be shown that the final state of the grid is uniquely determined regardless of what row or column is chosen in each operation.
Find the final state of the grid.

Constraints

1 \leq H, W \leq 100

a_{i, j} is . or #.

There is at least one black square in the whole grid.

Input

Input is given from Standard Input in the following format:

H W
a_{1, 1}...a_{1, W}
:
a_{H, 1}...a_{H, W}

Output

Print the final state of the grid in the same format as input (without the numbers of rows and columns); see the samples for clarity.

Sample Input 1

4 4
##.#
....
##.#
.#.#

Sample Output 1

###
###
.##

The second row and the third column in the original grid will be removed.

Sample Input 2

3 3
#..
.#.
..#

Sample Output 2

#..
.#.
..#

As there is no row or column that consists only of white squares, no operation will be performed.

Sample Input 3

4 5
.....
.....
..#..
.....

Sample Output 3

#

Sample Input 4

7 6
......
....#.
.#....
..#...
..#...
......
.#..#.

Sample Output 4

..#
#..
.#.
.#.
#.#

Solution in Rust (1.15.1) (judge verdict: Accepted)

pub trait FromFragment: Sized {
    fn from_fragment(s: &str) -> Result<Self, String>;
}
impl FromFragment for String {
    fn from_fragment(s: &str) -> Result<String, String> {
        Ok(s.to_owned())
    }
}
#[allow(unused_macros)]
macro_rules ! impl_from_fragment { ( $ ( $ t : ty ) * ) => { $ ( impl FromFragment for $ t { fn from_fragment ( s : & str ) -> Result <$ t , String > { use std :: str :: FromStr ; <$ t >:: from_str ( s ) . map_err ( | _ | { format ! ( "cannot parse \"{}\" as {}" , s , stringify ! ( $ t ) ) } ) } } ) * } ; }
impl_from_fragment ! ( isize usize i8 u8 i16 u16 i32 u32 i64 u64 f64 ) ;
pub trait FromLine: Sized {
    fn from_line(line: &str) -> Result<Self, String>;
}
impl<T: FromFragment> FromLine for T {
    fn from_line(line: &str) -> Result<T, String> {
        T::from_fragment(line.trim_right_matches('\n'))
    }
}
#[doc = " Reads arbitrary number of `T`s."]
impl<T: FromFragment> FromLine for Vec<T> {
    fn from_line(line: &str) -> Result<Vec<T>, String> {
        let mut result = Vec::new();
        for fragment in line.trim_right_matches('\n').split_whitespace() {
            match T::from_fragment(fragment) {
                Ok(v) => result.push(v),
                Err(msg) => {
                    return Err(format!(
                        "fragment {} of line \"{}\": {}",
                        result.len() + 1,
                        line,
                        msg
                    ))
                }
            }
        }
        Ok(result)
    }
}
#[allow(unused_macros)]
macro_rules ! impl_from_line_for_tuples { ( $ t : ident $ var : ident $ count : expr ) => ( ) ; ( $ t : ident $ var : ident $ count : expr ; $ ( $ inner_t : ident $ inner_var : ident $ inner_count : expr ) ;* ) => { impl_from_line_for_tuples ! ( $ ( $ inner_t $ inner_var $ inner_count ) ;* ) ; impl <$ t : FromFragment , $ ( $ inner_t : FromFragment ) ,*> FromLine for ( $ t , $ ( $ inner_t ) ,* ) { # [ allow ( unused_assignments ) ] fn from_line ( line : & str ) -> Result < ( $ t , $ ( $ inner_t ) ,* ) , String > { let fragments : Vec <& str > = line . trim_right_matches ( '\n' ) . split_whitespace ( ) . collect ( ) ; if fragments . len ( ) != $ count { return Err ( format ! ( "line \"{}\" has {} fragments, expected {}" , line , fragments . len ( ) , $ count ) ) ; } let mut iter = fragments . iter ( ) ; let mut n = 1 ; let $ var = <$ t >:: from_fragment ( iter . next ( ) . unwrap ( ) ) . map_err ( | msg | { format ! ( "fragment {} of line \"{}\": {}" , n , line , msg ) } ) ?; n += 1 ; $ ( let $ inner_var = <$ inner_t >:: from_fragment ( iter . next ( ) . unwrap ( ) ) . map_err ( | msg | { format ! ( "fragment {} of line \"{}\": {}" , n , line , msg ) } ) ?; n += 1 ; ) * Ok ( ( $ var , $ ( $ inner_var ) ,* ) ) } } } }
impl_from_line_for_tuples ! ( T4 x4 4 ; T3 x3 3 ; T2 x2 2 ; T1 x1 1 ) ;
#[macro_export]
#[allow(unused_macros)]
macro_rules ! read { ( ) => { let mut line = String :: new ( ) ; std :: io :: stdin ( ) . read_line ( & mut line ) . unwrap ( ) ; } ; ( $ pat : pat = $ t : ty ) => { let mut line = String :: new ( ) ; std :: io :: stdin ( ) . read_line ( & mut line ) . unwrap ( ) ; let $ pat = <$ t >:: from_line ( & line ) . unwrap ( ) ; } ; ( $ ( $ pat : pat = $ t : ty ) ,+ ) => { read ! ( ( $ ( $ pat ) ,* ) = ( $ ( $ t ) ,* ) ) ; } ; }
#[macro_export]
#[allow(unused_macros)]
macro_rules ! readls { ( $ ( $ pat : pat = $ t : ty ) ,+ ) => { $ ( read ! ( $ pat = $ t ) ; ) * } }
#[allow(unused_macros)]
macro_rules ! read_loop { ( $ pat : pat = $ t : ty ; $ block : block ) => { use std :: io :: BufRead ; let stdin = std :: io :: stdin ( ) ; for line in stdin . lock ( ) . lines ( ) { let line = line . expect ( "read from stdin failed" ) ; let $ pat = <$ t >:: from_line ( & line ) . unwrap ( ) ; $ block } } ; ( $ ( $ pat : pat = $ t : ty ) ,* ; $ block : block ) => { read_loop ! ( ( $ ( $ pat ) ,* ) = ( $ ( $ t ) ,* ) ; $ block ) ; } }
#[allow(unused_macros)]
macro_rules ! readn_loop { ( $ n : expr ; $ pat : pat = $ t : ty ; $ block : block ) => { use std :: io :: BufRead ; let stdin = std :: io :: stdin ( ) ; { let lock = stdin . lock ( ) ; for _ in 0 ..$ n { let line = String :: new ( ) ; lock . read_line ( & mut line ) . expect ( "read from stdin failed" ) ; let $ pat = <$ t >:: from_line ( & line ) . unwrap ( ) ; $ block } } } ; ( $ n : expr ; $ ( $ pat : pat = $ t : ty ) ,* ; $ block : block ) => { read_times_loop ! ( $ n ; ( $ ( $ pat ) ,* ) = ( $ ( $ t ) ,* ) ; $ block ) ; } }

fn main() {
    read!(_ = usize, w = usize);
    let mut lines = Vec::new();
    read_loop!(s = String; {
        lines.push(s);
    });
    let lines: Vec<String> = lines.into_iter().filter(|s| s.chars().any(|c| c == '#')).collect();
    let lines: Vec<Vec<char>> = lines.into_iter().map(|s| s.chars().collect()).collect();
    let mut skips = vec![false; w];
    for i in 0..w {
        skips[i] = lines.iter().all(|s| s[i] == '.');
    }
    for s in lines {
        for (i, c) in s.into_iter().enumerate() {
            if !skips[i] {
                print!("{}", c);
            }
        }
        println!();
    }
}