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hello-algo/zh-hant/codes/python/chapter_backtracking/subset_sum_i_naive.py

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"""
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]],
):
"""回溯演算法:子集和 I"""
# 子集和等於 target 時,記錄解
if total == target:
res.append(list(state))
return
# 走訪所有選擇
for i in range(len(choices)):
# 剪枝:若子集和超過 target ,則跳過該選擇
if total + choices[i] > target:
continue
# 嘗試:做出選擇,更新元素和 total
state.append(choices[i])
# 進行下一輪選擇
backtrack(state, target, total + choices[i], choices, res)
# 回退:撤銷選擇,恢復到之前的狀態
state.pop()
def subset_sum_i_naive(nums: list[int], target: int) -> list[list[int]]:
"""求解子集和 I包含重複子集"""
state = [] # 狀態(子集)
total = 0 # 子集和
res = [] # 結果串列(子集串列)
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"輸入陣列 nums = {nums}, target = {target}")
print(f"所有和等於 {target} 的子集 res = {res}")
print(f"請注意,該方法輸出的結果包含重複集合")