Our task is to print the element which occurs 3 consecutive times in a Python list.

Example :

Input : [4, 5, 5, 5, 3, 8]

Output : 5

Input : [1, 1, 1, 64, 23, 64, 22, 22, 22]

Output : 1, 22

Approach :

1. Create a list.
2. Create a loop for range size – 2.
3. Check if the element is equal to the next element.
4. Again check if the next element is equal to the next element.
5. If both conditions are satisfied then print the element.

Example 1 : Only one occurrence of a 3 consecutively occurring element.

# creating the array
arr = [4, 5, 5, 5, 3, 8]

# size of the list
size = len(arr)

# looping till length - 2
for i in range(size - 2):

	# checking the conditions
	if arr[i] == arr[i + 1] and arr[i + 1] == arr[i + 2]:

		# printing the element as the
		# conditions are satisfied
		print(arr[i])

Output :

5

Example 2 : Multiple occurrences of 3 consecutively occurring elements.

# creating the array
arr = [1, 1, 1, 64, 23, 64, 22, 22, 22]

# size of the list
size = len(arr)

# looping till length - 2
for i in range(size - 2):

	# checking the conditions
	if arr[i] == arr[i + 1] and arr[i + 1] == arr[i + 2]:

		# printing the element as the
		# conditions are satisfied
		print(arr[i])

Output :

1
22