# Algorithm Implementation/Sorting/Gnome sort

## CEdit

```void gnome_sort(int *array, int size){
int i, tmp;
for(i=1; i<size; ){
if(array[i-1] <= array[i])
++i;
else{
tmp = array[i];
array[i] = array[i-1];
array[i-1] = tmp;
--i;
if(i == 0)
i = 1;
}
}
}
```

## C++Edit

```#include <algorithm> // for std::swap
void gnomeSort( int *array, int size )
{
for ( int i = 1; i < size; ) {
if ( array[i-1] <= array[i] ) {
++i;
}
else {
std::swap( array[i-1], array[i] );
--i;
if ( i == 0 ) {
i = 1;
}
}
}
}
```

### C++ using bidirectional iteratorsEdit

```#include <algorithm> // for std::iter_swap

template <typename Iterator>
void gnome_sort(Iterator begin, Iterator end)
{
Iterator current = begin;
Iterator before_current;

while (current != end)
{
if (current == begin || *before_current <= *current)
{
++current;
}
else
{
std::iter_swap(before_current, current);
--current;
}
before_current = current;
--before_current;
}
}
```

### Optimized C++ using iteratorsEdit

```#include <algorithm> // for std::iter_swap

template <typename Iterator>
void gnome_sort(Iterator begin, Iterator end)
{
Iterator current = begin;
Iterator before_current;
size_t step = 1;

while (current != end)
{
if (current == begin || *before_current <= *current)
{
std::advance(current, step); // possible leap optimization
step = 1;
}
else
{
std::iter_swap(before_current, current);
--current;
++step;
}
before_current = current;
--before_current;
}
}
```

The optimized version makes the "gnome" (represented by the 'current' iterator here) leap back to the right i.e. to the place where it needed to swap the flower pots on its farthest reached position so far. This also avoids redundant comparisons. On average the optimization results in cutting the time by one/third on a modern x86 machine. (A wise gnome sort? :). However, the optimization works best if the iterators are random access iterators. Otherwise the algorithm works almost like the non-optimized version - it still avoids redundant comparisons though.

## C#Edit

```void GnomeSort( int[] array )
{
for ( int i = 1, temp_value; i < array.Length; )
{
if ( array[i-1] <= array[i] )
i += 1;
else
{
temp_value = array[i-1];
array[i-1] = array[i];
array[i] = temp_value;
i -= 1;
if ( i == 0 )
i = 1;
}
}
}
```

## FORTRANEdit

```SUBROUTINE gnome_sort(LIST, LENGTH)
INTEGER LIST, LENGTH, I, TEMP
DIMENSION LIST(LENGTH)
I = 2
WHILE (I .LE. LENGTH) DO
IF ((I .EQ. 1) .OR. (LIST(I-1) .LE. LIST(I))) THEN
I = I + 1
ELSE
TEMP = LIST(I)
LIST(I) = LIST(I-1)
LIST(I-1) = TEMP
I = I - 1
IF (I .EQ. 1) THEN
I = 2
END IF
END IF
END WHILE
END
```

## JavaEdit

```public class GnomeSort {
static void gnomeSort( int[] theArray ) {
for ( int index = 1; index < theArray.length; ) {
if ( theArray[index - 1] <= theArray[index] ) {
++index;
} else {
int tempVal = theArray[index];
theArray[index] = theArray[index - 1];
theArray[index - 1] = tempVal;
--index;
if ( index == 0 ) {
index = 1;
}
}
}
}
}
```

## JavaScriptEdit

```function gnomeSort(sortMe) {
i=0;
while (i < sortMe.length) {
if (i==0||sortMe[i-1] <= sortMe[i]) {
i++;
} else {
tmp=sortMe[i];
sortMe[i]=sortMe[i-1];
sortMe[--i]=tmp;
}
}
}
```

## LavishScriptEdit

This sorts an scope-accessible index:objectype (IndexName) passed by variable name, sorting by MemberName, which should be a numeric member of objecttype.

```method Gnomesort(string IndexName, string MemberName)
{
variable int i = 1

while \${i} <= \${\${IndexName}.Used}
{
if ( \${i} == 1 ) || \${\${IndexName}[\${Math.Calc[\${i}-1]}].\${MemberName}} <= \${\${IndexName}[\${i}].\${MemberName}}
{
i:Inc
}
else
{
\${IndexName}:Swap[\${i}, \${Math.Calc[\${i}-1]}]
i:Dec
}
}
}
```

## PerlEdit

```sub gnome_sort(@) {
my @list  = @_;
my \$size  = scalar(@list);
my \$right = 1;
while ( \$right < \$size ) {
my \$left = \$right - 1;
if ( \$list[\$left] <= \$list[\$right] ) {
\$right++;
}
else {
@list[ \$left, \$right ] = @list[ \$right, \$left ];
\$right-- if \$right > 1;
}
}
return @list;
}
```

## PHPEdit

```<?php
function gnome_sort(\$list)
{
for (\$i = 1; \$i < count(\$list);)
{
if (\$list[\$i-1] <= \$list[\$i]) {\$i++;}
else
{
\$temp = \$list[\$i];
\$list[\$i] = \$list[\$i-1];
\$list[\$i-1] = \$temp;
\$i--;
if (\$i == 0) {\$i = 1;}
}
}
return \$list;
}
?>
```

## PythonEdit

```def gnomeSort(items):
i = 0
n = len(items)
while i < n:
if i and items[i] < items[i-1]:
items[i], items[i-1] = items[i-1], items[i]
i -= 1
else:
i += 1
return

def teleportingGnomeSort(items):
i = j = 0
n = len(items)
while i < n:
if i and items[i] < items[i-1]:
items[i], items[i-1] = items[i-1], items[i]
i -= 1
else:
if i < j: # teleport!
i = j
j = i = i+1
return
```

## RubyEdit

```module GnomeSort
def self.sort(keys)
sort!(keys.clone)
end

def self.sort!(keys)
i, j = 1, 2
while i < keys.size
if keys[i-1] <= keys[i]
i, j = j, j+1
else
keys[i-1], keys[i] = keys[i], keys[i-1]
i -= 1 if i > 1
end
end
keys
end
end
```