Create OBST_recursive.py

Author: careermonk

dynamic-programming/OBST_recursive.py

@@ -0,0 +1,29 @@
+# Copyright (c) June 02, 2017 CareerMonk Publications and others.
+# E-Mail           		: [email protected]
+# Creation Date    		: 2017-06-02 06:15:46
+# Last modification		: 2017-06-02
+# Modified by		        : Narasimha Karumanchi
+# Book Title			: Algorithm Design Techniques
+# Warranty         		: This software is provided "as is" without any
+# 				 warranty; without even the implied warranty of
+# 				 merchantability or fitness for a particular purpose.
+
+def get_OBST(A, F, i, j, level):
+    if i > j:
+        return 0
+    min_value = float("inf")
+
+    for index in range(i, j + 1):
+        val = (get_OBST(A, F, i, index - 1, level + 1)   # left tree
+               + level * F[index]                                    # value at level
+               + get_OBST(A, F, index + 1, j, level + 1)) # right tree
+        min_value = min(val, min_value)
+
+    return min_value
+
+def OBST(A, F):
+    return get_OBST(A, F, 0, len(A) - 1, 1)
+
+A = [10, 12, 20, 35, 46]
+F = [34, 8, 50, 21, 16]
+print OBST(A, F)