Add tasks for all the new languages

Task/Quickselect-algorithm/Nim/quickselect-algorithm.nim

@@ -0,0 +1,19 @@
+proc qselect[T](a: var openarray[T]; k: int, inl = 0, inr = -1): T =
+  var r = if inr >= 0: inr else: a.high
+  var st = 0
+  for i in 0 .. < r:
+    if a[i] > a[r]: continue
+    swap a[i], a[st]
+    inc st
+
+  swap a[r], a[st]
+
+  if k == st:  a[st]
+  elif st > k: qselect(a, k, 0, st - 1)
+  else:        qselect(a, k, st, inr)
+
+let x = [9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
+
+for i in 0..9:
+  var y = x
+  echo i, ": ", qselect(y, i)

Task/Quickselect-algorithm/Phix/quickselect-algorithm.phix

@@ -0,0 +1,41 @@
+global function quick_select(sequence s, integer k)
+integer left = 1, right = length(s), pos
+object pivotv, tmp
+
+    while left<right do
+        pivotv = s[k];
+--      {s[k], s[right]} = {s[right], s[k]}
+        tmp = s[k]
+        s[k] = s[right]
+        s[right]=tmp
+        pos = left
+        for i=left to right do
+            if s[i]<pivotv then
+--              {s[i], s[pos]} = {s[pos], s[i]}
+                tmp = s[i]
+                s[i] = s[pos]
+                s[pos]=tmp
+                pos += 1
+            end if
+        end for
+--      {s[right], s[pos]} = {s[pos], s[right]}
+        tmp = s[right]
+        s[right] = s[pos]
+        s[pos]=tmp
+        if pos==k then exit end if
+        if pos<k then
+            left = pos + 1
+        else
+            right = pos - 1
+        end if
+    end while
+    return {s,s[k]}
+end function
+
+sequence s = {9, 8, 7, 6, 5, 0, 1, 2, 3, 4}
+integer r
+for i=1 to 10 do
+    {s,r} = quick_select(s,i)
+    printf(1," %d",r)
+end for
+{} = wait_key()

Task/Quickselect-algorithm/Ring/quickselect-algorithm.ring

@@ -0,0 +1,20 @@
+aList = [9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
+see partition(aList, 9, 4, 2) + nl
+
+func partition list, left, right, pivotIndex
+     pivotValue = list[pivotIndex]
+     temp = list[pivotIndex]
+     list[pivotIndex] = list[right]
+     list[right]  = temp
+     storeIndex = left
+     for i = left to right-1
+         if list[i] < pivotValue
+            temp = list[storeIndex]
+            list[storeIndex] = list[i]
+            list[i] = temp
+            storeIndex++ ok
+         temp = list[right]
+         list[right] = list[storeIndex]
+         list[storeIndex] = temp
+     next
+     return storeIndex

Task/Quickselect-algorithm/Sidef/quickselect-algorithm.sidef

@@ -0,0 +1,14 @@
+func quickselect(a, k) {
+    var pivot = a.pick;
+    var left  = a.grep{|i| i < pivot};
+    var right = a.grep{|i| i > pivot};
+
+    given(var l = left.len) {
+        when (k)     { pivot }
+        case (k < l) { __FUNC__(left, k) }
+        default      { __FUNC__(right, k - l - 1) }
+    }
+}
+
+var v = [9, 8, 7, 6, 5, 0, 1, 2, 3, 4];
+say v.range.map{|i| quickselect(v, i)};

Task/Quickselect-algorithm/Swift/quickselect-algorithm.swift

@@ -0,0 +1,20 @@
+func select<T where T : Comparable>(var elements: [T], n: Int) -> T {
+  var r = indices(elements)
+  while true {
+    let pivotIndex = partition(&elements, r)
+    if n == pivotIndex {
+      return elements[pivotIndex]
+    } else if n < pivotIndex {
+      r.endIndex = pivotIndex
+    } else {
+      r.startIndex = pivotIndex+1
+    }
+  }
+}
+
+for i in 0 ..< 10 {
+  let a = [9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
+  print(select(a, i))
+  if i < 9 { print(", ") }
+}
+println()

Task/Quickselect-algorithm/jq/quickselect-algorithm-1.jq

@@ -0,0 +1,30 @@
+# Emit the k-th smallest item in the input array,
+# or nothing if k is too small or too large.
+# The smallest corresponds to k==1.
+# The input array may hold arbitrary JSON entities, including null.
+def quickselect(k):
+
+  def partition(pivot):
+    reduce .[] as $x
+      # state: [less, other]
+      ( [ [], [] ];                       # two empty arrays:
+        if    $x  < pivot
+        then .[0] += [$x]                 # add x to less
+        else .[1] += [$x]                 # add x to other
+        end
+      );
+
+  # recursive inner function has arity 0 for efficiency
+  def qs:  # state: [kn, array] where kn counts from 0
+    .[0] as $kn
+     | .[1] as $a
+    | $a[0] as $pivot
+    | ($a[1:] | partition($pivot)) as $p
+    | $p[0] as $left
+    | ($left|length) as $ll
+    | if   $kn == $ll then $pivot
+      elif $kn <  $ll then [$kn, $left] | qs
+      else [$kn - $ll - 1, $p[1] ] | qs
+      end;
+
+  if length < k or k <= 0 then empty else [k-1, .] | qs end;

Task/Quickselect-algorithm/jq/quickselect-algorithm-2.jq

@@ -0,0 +1,3 @@
+(0, 12, range(1;11)) as $k
+ | [9, 8, 7, 6, 5, 0, 1, 2, 3, 4] | quickselect($k)
+ | "k=\($k) => \(.)"

Task/Quickselect-algorithm/jq/quickselect-algorithm-3.jq

@@ -0,0 +1,12 @@
+$ jq -n -r -f quickselect.jq
+k=1 => 0
+k=2 => 1
+k=3 => 2
+k=4 => 3
+k=5 => 4
+k=6 => 5
+k=7 => 6
+k=8 => 7
+k=9 => 8
+k=10 => 9
+$