Binary search and selection sort in Perl

* Create 01_binary_search.pl

* Typo fixed in 01_binary_search.pl

* Create 01_selection_sort.pl
This commit is contained in:
biosta
2018-04-20 18:21:28 +03:00
committed by Aditya Bhargava
parent ea74644c95
commit f24b9a6e35
2 changed files with 75 additions and 0 deletions

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sub binary_search {
my ( $item, @list ) = @_;
# The borders inside where we are searching in:
my $low = 0;
my $high = $#list;
# Do that until found or until just one element remains:
while ( $low <= $high ) {
# Detect the middle of the array:
my $mid = int( ( $low + $high ) / 2 );
my $guess = $list[$mid];
# We found it out:
if ( $guess == $item ) {
return $mid;
}
# The guess is too high, decrease it:
elsif ( $guess > $item ) {
$high = --$mid;
}
# The guess is too low, increase it:
else {
$low = ++$mid;
}
}
# Nothing at all found:
return 'None';
}
my @my_list = qw /1 3 5 7 9/;
# Should display "1":
print binary_search( 3, @my_list ), "\n";
# Should display "None":
print binary_search( -1, @my_list ), "\n";

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# Detect the smallest value in an array
sub findSmallest {
my @arr = @_;
my $smallest = $arr[0]; # Keep the smallest value
my $smallest_index = 0; # Keep the index of the smallest value
for ( my $i = 1; $i <= $#arr; $i++ ) {
$smallest_index = $i if $arr[$i] < $smallest;
}
return $smallest_index;
}
# Sort array
sub selectionSort {
my @arr = @_;
my @newArr = ();
for ( 0 .. $#arr ) {
my $smallest_index = findSmallest(@arr); # Find the smallest element in the array
push @newArr, $arr[$smallest_index]; # Add it to the new array
splice( @arr, $smallest_index, 1 ); # Delete that element
}
return @newArr;
}
print join( ' ', selectionSort( 5, 3, 6, 2, 10 ) ), "\n";