#!/usr/bin/perl
use strict;
use warnings;
use Sort::Naturally qw/ nsort /;
use List::Util qw / max /;

@ARGV = qw/ 148N.txt 162N.txt 174N.txt 175N.txt /;
my %data;

while (<>) {
	my ($chr, @start_stop) = split;	
	push @{ $data{$chr} }, \@start_stop;
}

for my $chr (nsort keys %data) {
	my ($first, @in_order) =  sort {$a->[0] <=> $b->[0]} @{ $data{$chr} };
	
	my ($lo, $hi) = @$first;
	
	my $merged;
	
	for my $aref (@in_order) { # array reference
		my ($start, $stop) = @$aref;
		if ($start <= $hi) {
			$hi = max $hi, $stop;
			$merged++;
		}
		else {
			printf "%s %s %s merged: %s\n", $chr, $lo, $hi, $merged + 1 if $merged;
			#print "$chr $lo $hi\n" if $merged;
			($lo, $hi) = ($start, $stop);
			$merged = 0;	
		}	
	}
	printf "%s %s %s merged: %s\n", $chr, $lo, $hi, $merged + 1 if $merged;
	#print "$chr $lo $hi\n" if $merged;
}