Adding sum of subsets (#929)

Author: jpg-130

Diff for: dynamic_programming/sum_of_subset.py

@@ -0,0 +1,34 @@
+def isSumSubset(arr, arrLen, requiredSum):
+
+    # a subset value says 1 if that subset sum can be formed else 0
+    #initially no subsets can be formed hence False/0
+    subset = ([[False for i in range(requiredSum + 1)] for i in range(arrLen + 1)])
+
+    #for each arr value, a sum of zero(0) can be formed by not taking any element hence True/1
+    for i in range(arrLen + 1):
+        subset[i][0] = True
+
+    #sum is not zero and set is empty then false
+    for i in range(1, requiredSum + 1):
+        subset[0][i] = False
+
+    for i in range(1, arrLen + 1):
+        for j in range(1, requiredSum + 1):
+            if arr[i-1]>j:
+                subset[i][j] = subset[i-1][j]
+            if arr[i-1]<=j:
+                subset[i][j] = (subset[i-1][j] or subset[i-1][j-arr[i-1]])
+
+    #uncomment to print the subset
+    # for i in range(arrLen+1):
+    #     print(subset[i])
+
+    return subset[arrLen][requiredSum]
+
+arr = [2, 4, 6, 8]
+requiredSum =  5
+arrLen = len(arr)
+if isSumSubset(arr, arrLen, requiredSum):
+    print("Found a subset with required sum")
+else:
+    print("No subset with required sum")