Sorting algorithms/Quicksort: Difference between revisions

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→‎{{header|Phix}}: added syntax colouring the hard way
m (Reapplied prior datatype update.)
m (→‎{{header|Phix}}: added syntax colouring the hard way)
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=={{header|Phix}}==
<!--<lang Phix>function quick_sort(sequence xphixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
--
-- put x into ascending order using recursive quick sort
<span style="color: #008080;">function</span> <span style="color: #000000;">quick_sort</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
--
<span style="color: #000080;font-style:italic;">--
integer n, last, mid
-- put x into ascending order using recursive quick sort
object xi, midval
--</span>
 
<span style="color: #004080;">integer</span> <span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
n = length(x)
<span style="color: #008080;">if</span> <span style="color: #000000;">n</span><span style="color: #0000FF;"><</span><span style="color: #000000;">2</span> <span style="color: #008080;">then</span>
if n<2 then
<span style="color: #008080;">return</span> <span style="color: #000000;">x</span> <span style="color: #000080;font-style:italic;">-- already sorted (trivial case)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
end if
 
<span style="color: #004080;">integer</span> <span style="color: #000000;">mid</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">((</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">),</span>
mid = floor((n+1)/2)
<span style="color: #000000;">last</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
midval = x[mid]
<span style="color: #004080;">object</span> <span style="color: #000000;">midval</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">mid</span><span style="color: #0000FF;">]</span>
x[mid] = x[1]
<span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">mid</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
 
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">2</span> <span style="color: #008080;">to</span> <span style="color: #000000;">n</span> <span style="color: #008080;">do</span>
last = 1
<span style="color: #004080;">object</span> <span style="color: #000000;">xi</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span>
for i=2 to n do
<span style="color: #008080;">if</span> <span style="color: #000000;">xi</span><span style="color: #0000FF;"><</span><span style="color: #000000;">midval</span> <span style="color: #008080;">then</span>
xi = x[i]
<span style="color: #000000;">last</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
if xi<midval then
<span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">last</span><span style="color: #0000FF;">]</span>
last += 1
<span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">last</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">xi</span>
x[i] = x[last]
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
x[last] = xi
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
end if
end for
<span style="color: #008080;">return</span> <span style="color: #000000;">quick_sort</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">2</span><span style="color: #0000FF;">..</span><span style="color: #000000;">last</span><span style="color: #0000FF;">])</span> <span style="color: #0000FF;">&</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">midval</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">&</span> <span style="color: #000000;">quick_sort</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">[</span><span style="color: #000000;">last</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">n</span><span style="color: #0000FF;">])</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
return quick_sort(x[2..last]) & {midval} & quick_sort(x[last+1..n])
end function
<span style="color: #0000FF;">?</span><span style="color: #000000;">quick_sort</span><span style="color: #0000FF;">({</span><span style="color: #000000;">5</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"oranges"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"and"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"apples"</span><span style="color: #0000FF;">})</span>
 
<!--</lang>-->
?quick_sort({5,"oranges","and",3,"apples"})</lang>
{{out}}
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