#!/usr/bin/perl -w
# Read a file into an array.
# Find pairs of same integers and print these pairs and their positions.
# Finally, sort the indices by range and print a diagram.
# Written by Myst Shen in May,2008.


open (DATA, "data_file") || die "opening file: $!";
foreach (<DATA>){
    push (@words, split);
}
close (DATA);


@words2 = @words;
$width = $#words;

$i = 0;
foreach $item (@words){
    $i++;
    if ( $item =~ /\d/ ){
        for ( $j=0; $j<@words-$i; $j++ ) {
            if ( $words[$i+$j] =~ /\d/ ) {
                if ( $words[$i+$j] == $item ){
                    $idx = $i+$j+1;
                    push (@arr1, "($item,$words[$i+$j])");
                    push (@arr2, "[$i,$idx]");
                    splice (@words, $i+$j, 1, "c");
                    last;
                }
            }
        }
    }
}


sub by_range {
    @aa = split (/\[|,|\]/,$a);
    @bb = split (/\[|,|\]/,$b);
    return ( $aa[2] - $aa[1] <=> $bb[2] - $bb[1] );
}


@arr3 = reverse (sort by_range @arr2);


print "The array is : \n";
print "@words2\n\n";


printf ("%d pairs found:\n",$#arr1 + 1);
print "@arr1\n\n";


print "The indices are:\n";
print "@arr2\n\n";


print "Sort the indices by range:\n";
print "@arr3\n\n";


print "Print a diagram: \n\n";


@pr = (" ");
for ( $m=0; $m<=$width; $m++ ) {
    @pr = (" ", @pr);
}


for ( $n=0; $n<=$#arr1; $n++ ) {
    @aa = split (/\[|,|\]/, $arr3[0]);
    @pr2 = @pr;
    $line = "* " x ($aa[2]-$aa[1]+1);
    splice (@pr2, $aa[1]-1, ($aa[2]-$aa[1])/2, $line);
    print "@pr2\n";
    shift @arr3;
}

print "@words2\n\n";