Python: List integers containing exactly three distinct values, such that no integer repeats twice consecutively

Last update on May 30 2025 11:49:47 (UTC/GMT +8 hours)

Four Distinct Values Non-Consecutive

Write a Python program to find a list of integers containing exactly four distinct values, such that no integer repeats twice consecutively among the first twenty entries.

Note: The list needs to have length greater than ten.)

Input:
[1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]
Output:
True

Input:
[1, 2, 3, 3, 1, 2, 3, 3, 1, 2, 3, 3, 1, 2, 3, 3]
Output:
False

Input:
[1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]
Output:
False

Visual Presentation:

Sample Solution:

Python Code:

# License: https://bit.ly/3oLErEI

# Define a function named 'test' that takes a list of integers 'nums' as input
def test(nums):
    # Check if no integer in 'nums' repeats consecutively and if there are exactly four distinct values in 'nums'
    return all([nums[i] != nums[i + 1] for i in range(len(nums) - 1)]) and len(set(nums)) == 4

# Create a list of integers 'nums' with specific elements
nums = [1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]

# Print the original list
print("Original list:")
print(nums)

# Print a message indicating the condition being checked on the list
print("Check said list of integers containing exactly four distinct values, such that no integer repeats twice consecutively:")

# Print the result of the test function applied to the 'nums' list
print(test(nums))

# Create a different list of integers 'nums' with specific elements
nums = [1, 2, 3, 3, 1, 2, 3, 3, 1, 2, 3, 3, 1, 2, 3, 3]

# Print the original list
print("\nOriginal list:")
print(nums)

# Print a message indicating the condition being checked on the list
print("Check said list of integers containing exactly four distinct values, such that no integer repeats twice consecutively:")

# Print the result of the test function applied to the modified 'nums' list
print(test(nums))

# Create another list of integers 'nums' with specific elements
nums = [1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]

# Print the original list
print("\nOriginal list:")
print(nums)

# Print a message indicating the condition being checked on the list
print("Check said list of integers containing exactly four distinct values, such that no integer repeats twice consecutively:")

# Print the result of the test function applied to the modified 'nums' list
print(test(nums))

Sample Output:

Original list:
[1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]
Check said list of integers containing exactly four distinct values, such that no integer repeats  twice consecutively:
True

Original list:
[1, 2, 3, 3, 1, 2, 3, 3, 1, 2, 3, 3, 1, 2, 3, 3]
Check said list of integers containing exactly four distinct values, such that no integer repeats  twice consecutively:
False

Original list:
[1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]
Check said list of integers containing exactly four distinct values, such that no integer repeats  twice consecutively:
False

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to verify that a list contains exactly four distinct values and that no value is repeated consecutively.
• Write a Python program to count unique elements in a list and check that none appear twice in a row within the first twenty entries.
• Write a Python program to iterate over a list and ensure it has exactly four unique numbers and that no adjacent pair are identical.
• Write a Python program to use slicing and set operations to confirm that the first twenty elements of a list have four distinct values with no consecutive duplicates.

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