Python – Non K distant elements

Given a list, the task is to write a Python program to extract all the elements such that no element is at K distant from one other.

Examples:

Input : test_list = [8, 10, 16, 20, 3, 1, 7], K = 2 
Output : [16, 20, 7] 
Explanation : 16 + 2 = 18, 16 – 2 = 14, both are not in list, hence filtered.

Input : test_list = [8, 10, 16, 20], K = 2 
Output : [16, 20, 7] 
Explanation : 16 + 2 = 18, 16 – 2 = 14, both are not in list, hence filtered. 

Method #1: Using loop

In this we iterate for all the elements and using in operator check for each element if has element at K distance from it, if found, its not included in list.

Python3

# Python3 code to demonstrate working of
# Non K distant elements
# Using loop

# initializing list
test_list = [8, 10, 16, 20, 3, 1, 7]

# printing original list
print("The original list is : " + str(test_list))

# initializing K
K = 2

res = []
for ele in test_list:

    # check for K distant
    if ele + K not in test_list and ele - K not in test_list:
        res.append(ele)

# printing result
print("The filtered List : " + str(res))

Output

The original list is : [8, 10, 16, 20, 3, 1, 7]
The filtered List : [16, 20, 7]

Time Complexity: O(n)
Auxiliary Space: O(n)

Method #2: Using list comprehension

In this, we perform task of filtering and iteration using 1 liner using list comprehension.

Python3

# Python3 code to demonstrate working of
# Non K distant elements
# Using list comprehension

# initializing list
test_list = [8, 10, 16, 20, 3, 1, 7]

# printing original list
print("The original list is : " + str(test_list))

# initializing K
K = 2

# using list comprehension to get all elements of non K distance
res = [ele for ele in test_list if ele +
       K not in test_list and ele - K not in test_list]

# printing result
print("The filtered List : " + str(res))

Output

The original list is : [8, 10, 16, 20, 3, 1, 7]
The filtered List : [16, 20, 7]

Time Complexity: O(n)
Auxiliary Space: O(n)