Is Check Good Integer easy or hard?

Check Good Integer is categorized as an Easy problem. The logic involves basic iteration through digits and simple comparisons, making it suitable for beginners practicing loops, conditions, and number handling.

Check Good Integer Python/Java solution

Both Python and Java solutions usually follow the same pattern: extract digits using modulo and division or convert the number to a string and compare characters. Each approach runs in linear time relative to the number of digits.

How to solve Check Good Integer in O(n)?

Treat n as the number of digits in the integer. Extract digits using n % 10 and n // 10 while comparing each digit with the first extracted digit. If all digits match, return true; otherwise return false. This performs a single linear scan across the digits.

What is the best approach for Check Good Integer?

The most efficient approach iterates through the digits using modulo and division. Store the last digit and compare it with every other digit extracted from the number. This runs in O(d) time where d is the number of digits, and uses O(1) extra space.

Is Check Good Integer asked at Google/Amazon/Meta?

Digit validation problems similar to Check Good Integer appear in coding interviews at large tech companies. They are typically used as warm‑up problems to test understanding of number manipulation, loops, and basic conditional logic.

What data structure is used in Check Good Integer?

No complex data structure is required. The optimal approach works directly with integer arithmetic. A string representation of the number may be used in an alternative solution for easier iteration over digits.

What is the time complexity of Check Good Integer?

The time complexity is O(d), where d is the number of digits in the integer. Each digit is checked exactly once to verify that it matches the reference digit. Space complexity can be O(1) with arithmetic digit extraction or O(d) if using string conversion.

3959. Check Good Integer - Practice Online

You are given a positive integer n.

Let digitSum be the sum of the digits of n, and let squareSum be the sum of the squares of the digits of n.

An integer is called good if squareSum - digitSum >= 50.

Return true if n is good. Otherwise, return false.

Example 1:

Input: n = 1000

Output: false

Explanation:

The digits of 1000 are 1, 0, 0, and 0.
The digitSum is 1 + 0 + 0 + 0 = 1.
The squareSum is 1² + 0² + 0² + 0² = 1.
The squareSum - digitSum is 1 - 1 = 0. As 0 is not greater than or equal to 50, the output is false.

Example 2:

Input: n = 19

Output: true

Explanation:

The digits of 19 are 1 and 9.
The digitSum is 1 + 9 = 10.
The squareSum is 1² + 9² = 1 + 81 = 82.
The squareSum - digitSum is 82 - 10 = 72. As 72 is greater than or equal to 50, the output is true.

Constraints:

1 <= n <= 10⁹