use strict;
use warnings;

#========================================
# Algorithms
#========================================

sub ranges_javafan {
  my ($M, $N) = @_;
  return [ map {[int($_*($M+1)/$N)
                 , int(($_+1)*(($M+1)/$N))-1]
              } 0..$N - 1];
}

#----------------------------------------

sub ranges_javafan_buk {
  my ($M, $N) = @_;
  my $STEP = ( $M + 1 ) / $N;
  return [ map [int( $_ * $STEP ), int( ( $_+1 ) * $STEP ) -1]
           , 0 .. $N - 1];
}

#----------------------------------------

sub ranges_elisheva_ikegami {
  my ($M, $N) = @_;
  my $r = ($M+1)%$N;
  my $q = ($M+1-$r)/$N;
  my $iEnd=0;
  return [ map { my $iStart=$iEnd; [$iStart, ($iEnd+=$_) - 1]
               } (($q+1) x $r, ($q) x ($N-$r)) ];
}

#========================================
# Check of final element of range
#========================================

sub roundCheck {
  my ($cr, $M) = @_;
  my $iTotal=0;
  my $iErrors=0;
  for my $m (1..$M) {
    for my $n (1..$m) {
      $iTotal++;
      my $aRanges = $cr->($m, $n);
      my $iFinal = $aRanges->[-1][1];
      if ($iFinal != $m) {
        $iErrors++;
        # Uncomment here to see individual errors
        # ---------------------------------------
        # print "($m,$n) ==> final=$iFinal\n";
      }
    }
  }
  printf "Error rate: %s\n", ($iErrors*100/$iTotal);
}
#-------------------------------------------------------

print "Javafan:\n";
roundCheck(\&ranges_javafan, 100);
print "Javafan_buk:\n";
roundCheck(\&ranges_javafan_buk, 100);
print "elisheva_ikegami\n";
roundCheck(\&ranges_elisheva_ikegami, 100);

#outputs (Debian Linux - Lenny, perl 5.10.0,  32-bit)
Javafan:
Error rate: 2.47524752475248
Javafan_buk:
Error rate: 2.47524752475248
elisheva_ikegami
Error rate: 0
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