# Program to check we can find four elements whose sum is same as k or not in Python

Suppose we have a list of numbers called nums and a value k, we have to check whether there are four unique elements in the list that add up to k.

So, if the input is like nums = [11, 4, 6, 10, 5, 1] k = 25, then the output will be True, as we have [4, 6, 10, 5] whose sum is 25.

To solve this, we will follow these steps −

• sort the list nums

• n := size of nums

• for i in range 0 to n − 4, do

• for j in range i + 1 to n − 3, do

• l := j + 1, h := size of nums − 1

• while l < h, do

• summ := nums[i] + nums[j] + nums[l] + nums[h]

• if summ is same as k, then

• return True

• otherwise when summ < k, then

• l := l + 1

• otherwise,

• h := h − 1

• return False

Let us see the following implementation to get better understanding −

## Example

Live Demo

class Solution:
def solve(self, nums, k):
nums.sort()
n = len(nums)
for i in range(n - 3):
for j in range(i + 1, n - 2):
l, h = j + 1, len(nums) - 1
while l < h:
summ = nums[i] + nums[j] + nums[l] + nums[h]
if summ == k:
return True
elif summ < k:
l += 1
else:
h −= 1
return False
ob1 = Solution()
nums = [11, 4, 6, 10, 5, 1]
k = 25
print(ob1.solve(nums, k))

## Input

[11, 4, 6, 10, 5, 1], 25

## Output

True

Updated on: 21-Oct-2020

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