How to make combination, if any one of the element exists that can be added to make sum?

问题

To find all possible combinations that can be added to make given sum. Combinations can be formed with multiple elements and also if any single element exists.

Input:

l1 = [9,1, 2, 7, 6, 1, 5] 
target = 8

**Constraints**
1<=(len(l1))<=500000
1<=each_list_element<=1000

Output:

Format : {index:element}
{1:1, 5:1, 4:6}   #Indices : 1,5,4   Elements : 1,1,6
{1:1, 2:2,  6:5}
{5:1, 2:2,  6:5}
{1:1,  3:7}
{5:1,  3:7}
{2:2,  4:6}

More Scenarios:

Input = [4,6,8,5,3]
target = 3
Output {4:3}

Input = [4,6,8,3,5,3]
target = 3
Output {5:3,3:3}

Input = [1,2,3,15]
target = 15
Output {3:15}

Below code covers for all above scenarios.

Scenarios to be handled, along with above.

Input =[1,6,7,1,3] 
target=5
Output={0:1,3:1,4:3} , {0:1,0:1,4:3}, {3:1,3:1,4:3}

Input=[9,6,8,1,7] 
target=5 
Output={3:1,3:1,3:1,3:1,3:1}

As suggested by @Chris Doyle in previous question, will be using that code. (How to find indices and combinations that adds upto given sum?)

Code:

from itertools import combinations


def find_sum_with_index(l1, target):
    index_vals = [iv for iv in enumerate(l1) if iv[1] < target]
    for r in range(1, len(index_vals) + 1):
        for perm in combinations(index_vals, r):
            if sum([p[1] for p in perm]) == target:
                yield perm


l1 = [9, 1, 2, 7, 6, 1, 5]
target = 8
for match in find_sum_with_index(l1, target):
    print(dict(match))

回答1:

You can use dictionary comprehension

from itertools import combinations
l1 = [9,1, 2, 7, 6, 1, 5] 
target = 8

for i in range(len(l1)):
  for c in combinations(l1,i):
      if sum(c) == target:
        res = { i:x for i,x in enumerate(c)}
        print(res)

来源：https://stackoverflow.com/questions/62360916/how-to-make-combination-if-any-one-of-the-element-exists-that-can-be-added-to-m

标签

python-3.x

list

dictionary

itertools