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perl/Examples/Chap3/fib-cached

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+
+
+###
+### fib-cached
+###
+
+## Chapter 3 section 2
+
+# Compute the number of pairs of rabbits alive in month n
+{ my %cache;
+  sub fib {
+    my ($month) = @_;
+    unless (exists $cache{$month}) {
+      if ($month < 2) { $cache{$month} = 1 }
+      else {
+        $cache{$month} = fib($month-1) + fib($month-2);
+      }
+    } 
+    return $cache{$month};
+  }
+}