如何编写一个通用的 function 来找到那些总和为零的数组元素？

Question

I have created a program which that takes as input an array of positive and negative numbers (0 excluded) and return those items from the array whose sum is 0. If no such items exist return, then return “No Elements found”. Here I have written separate functions for twoSum, threeSUM, fourSum... but I want to have general function which will check for nSum (n is the number of elements of array) eg In this list [-4, -3, -2, -1, 10], it should return -4, -3, -2, -1 and 10 there are 5 elements whose sum is 0. I am sharing my code.

def twoSum(arr,n,x,lp,rp):
    while lp<rp:
        if arr[lp] + arr[rp] == x:
            return True,arr[lp],arr[rp]
        elif arr[lp] + arr[rp] < x:
            lp+=1
        else:
            rp-=1
    return False,0,0

def threeSum(arr,n,x,firstIndex):
    for i in range(firstIndex,n-2):
        check,a,b = twoSum(arr,n,x-arr[i],i+1,n-1)
        if check:
            return True,arr[i],a,b
    return False,0,0,0
            
def finding_numbers(arr, n):
    if arr[0]<0:
        check,a,b = twoSum(arr,n,0,0,n-1)
        if check:
            return a,b
        
        check,a,b,c = threeSum(arr,n,0,0)
        if check:
            return a,b,c
          
        for i in range(n-3):
            check,a,b,c = threeSum(arr,n,-arr[i],i+1)
            if check:
                return arr[i],a,b,c
    return 'No Elements found'

finding_numbers(array, n)

Answer 1

You can use the help of the combinations function from itertools:

Code:

from itertools import combinations

def combinations_that_sum_zero(arr):
    return [list(comb) for i in range(1, len(arr) + 1) for comb in combinations(arr, i) if sum(comb) == 0]

arr = [1, 2, 3, -3, 4, 5, -6]
print(combinations_that_sum_zero(arr))

Output:

[[3, -3], [1, 2, -3], [1, 5, -6], [2, 4, -6], [1, 2, 3, -6], [-3, 4, 5, -6], [1, 3, -3, 5, -6], [2, 3, -3, 4, -6]]