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sum_of_subset.py
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sum_of_subset.py
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def is_sum_subset(arr: list[int], required_sum: int) -> bool:
"""
>>> is_sum_subset([2, 4, 6, 8], 5)
False
>>> is_sum_subset([2, 4, 6, 8], 14)
True
"""
# a subset value says 1 if that subset sum can be formed else 0
# initially no subsets can be formed hence False/0
arr_len = len(arr)
subset = [[False] * (required_sum + 1) for _ in range(arr_len + 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(arr_len + 1):
subset[i][0] = True
# sum is not zero and set is empty then false
for i in range(1, required_sum + 1):
subset[0][i] = False
for i in range(1, arr_len + 1):
for j in range(1, required_sum + 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]]
return subset[arr_len][required_sum]
if __name__ == "__main__":
import doctest
doctest.testmod()