sum_of_subset.py

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")