Data commit

Task/Catalan-numbers/Tcl/catalan-numbers-1.tcl

@@ -0,0 +1,19 @@
+package require Tcl 8.5
+
+# Memoization wrapper
+proc memoize {function value generator} {
+    variable memoize
+    set key $function,$value
+    if {![info exists memoize($key)]} {
+	set memoize($key) [uplevel 1 $generator]
+    }
+    return $memoize($key)
+}
+
+# The simplest recursive definition
+proc tcl::mathfunc::catalan n {
+    if {[incr n 0] < 0} {error "must not be negative"}
+    memoize catalan $n {expr {
+	$n == 0 ? 1 : 2 * (2*$n - 1) * catalan($n - 1) / ($n + 1)
+    }}
+}

Task/Catalan-numbers/Tcl/catalan-numbers-2.tcl

@@ -0,0 +1,3 @@
+for {set i 0} {$i < 15} {incr i} {
+    puts "C_$i = [expr {catalan($i)}]"
+}