Create distinct_subsequences_dp.py

Author: careermonk

dynamic-programming/distinct_subsequences_dp.py

@@ -0,0 +1,30 @@
+# 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 distinct_subsequences(S, T):
+	m = len(S)
+	n = len(T)
+
+	C = [[0 for _ in xrange(n+1)] for _ in xrange(m+1)]
+	for j in xrange(n+1):
+	    C[0][j] = 0
+	for i in xrange(m+1):
+	    C[i][0] = 1
+
+	for i in xrange(1, m+1):
+	    for j in xrange(1, n+1):
+		if S[i-1]==T[j-1]:
+		    C[i][j] = C[i-1][j]+C[i-1][j-1]
+		else:
+		    C[i][j] = C[i-1][j]
+
+	return C[m][n]
+
+print distinct_subsequences("abadcb", "ab")