Data commit

Task/Quickselect-algorithm/PowerShell/quickselect-algorithm.psh

@@ -0,0 +1,31 @@
+ function partition($list, $left, $right, $pivotIndex) {
+     $pivotValue = $list[$pivotIndex]
+     $list[$pivotIndex], $list[$right] = $list[$right], $list[$pivotIndex]
+     $storeIndex = $left
+     foreach ($i in $left..($right-1)) {
+         if ($list[$i] -lt $pivotValue) {
+             $list[$storeIndex],$list[$i] = $list[$i], $list[$storeIndex]
+             $storeIndex += 1
+         }
+     }
+     $list[$right],$list[$storeIndex] = $list[$storeIndex], $list[$right]
+     $storeIndex
+}
+
+function rank($list, $left, $right, $n) {
+    if ($left -eq $right) {$list[$left]}
+    else {
+        $pivotIndex = Get-Random -Minimum $left -Maximum $right
+        $pivotIndex = partition $list $left $right $pivotIndex
+        if ($n -eq $pivotIndex) {$list[$n]}
+        elseif ($n -lt $pivotIndex) {(rank $list $left ($pivotIndex - 1) $n)}
+        else {(rank $list ($pivotIndex+1) $right $n)}
+    }
+}
+
+function quickselect($list) {
+    $right = $list.count-1
+    foreach($left in 0..$right) {rank $list $left $right $left}
+}
+$arr = @(9, 8, 7, 6, 5, 0, 1, 2, 3, 4)
+"$(quickselect $arr)"