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* Adding nqueens.py for backtracking * Adding sum_of_subsets.py for backtracking * Update nqueens.py * Rename nqueens.py to n_queens.py * Deleting /other/n_queens.py
45 lines
1.4 KiB
Python
45 lines
1.4 KiB
Python
'''
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The sum-of-subsetsproblem states that a set of non-negative integers, and a value M,
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determine all possible subsets of the given set whose summation sum equal to given M.
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Summation of the chosen numbers must be equal to given number M and one number can
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be used only once.
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'''
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def generate_sum_of_subsets_soln(nums, max_sum):
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result = []
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path = []
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num_index = 0
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remaining_nums_sum = sum(nums)
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create_state_space_tree(nums, max_sum, num_index, path,result, remaining_nums_sum)
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return result
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def create_state_space_tree(nums,max_sum,num_index,path,result, remaining_nums_sum):
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'''
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Creates a state space tree to iterate through each branch using DFS.
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It terminates the branching of a node when any of the two conditions
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given below satisfy.
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This algorithm follows depth-fist-search and backtracks when the node is not branchable.
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'''
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if sum(path) > max_sum or (remaining_nums_sum + sum(path)) < max_sum:
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return
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if sum(path) == max_sum:
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result.append(path)
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return
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for num_index in range(num_index,len(nums)):
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create_state_space_tree(nums, max_sum, num_index + 1, path + [nums[num_index]], result, remaining_nums_sum - nums[num_index])
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'''
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remove the comment to take an input from the user
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print("Enter the elements")
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nums = list(map(int, input().split()))
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print("Enter max_sum sum")
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max_sum = int(input())
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'''
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nums = [3, 34, 4, 12, 5, 2]
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max_sum = 9
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result = generate_sum_of_subsets_soln(nums,max_sum)
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print(*result) |