You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
51 lines
1.5 KiB
51 lines
1.5 KiB
"""
|
|
File: subset_sum_i_naive.py
|
|
Created Time: 2023-06-17
|
|
Author: krahets (krahets@163.com)
|
|
"""
|
|
|
|
|
|
def backtrack(
|
|
state: list[int],
|
|
target: int,
|
|
total: int,
|
|
choices: list[int],
|
|
res: list[list[int]],
|
|
):
|
|
"""Backtracking algorithm: Subset Sum I"""
|
|
# When the subset sum equals target, record the solution
|
|
if total == target:
|
|
res.append(list(state))
|
|
return
|
|
# Traverse all choices
|
|
for i in range(len(choices)):
|
|
# Pruning: if the subset sum exceeds target, skip that choice
|
|
if total + choices[i] > target:
|
|
continue
|
|
# Attempt: make a choice, update elements and total
|
|
state.append(choices[i])
|
|
# Proceed to the next round of selection
|
|
backtrack(state, target, total + choices[i], choices, res)
|
|
# Retract: undo the choice, restore to the previous state
|
|
state.pop()
|
|
|
|
|
|
def subset_sum_i_naive(nums: list[int], target: int) -> list[list[int]]:
|
|
"""Solve Subset Sum I (including duplicate subsets)"""
|
|
state = [] # State (subset)
|
|
total = 0 # Subset sum
|
|
res = [] # Result list (subset list)
|
|
backtrack(state, target, total, nums, res)
|
|
return res
|
|
|
|
|
|
"""Driver Code"""
|
|
if __name__ == "__main__":
|
|
nums = [3, 4, 5]
|
|
target = 9
|
|
res = subset_sum_i_naive(nums, target)
|
|
|
|
print(f"Input array nums = {nums}, target = {target}")
|
|
print(f"All subsets equal to {target} res = {res}")
|
|
print(f"The result of this method includes duplicate sets")
|