leetcode

Convert Integer to the Sum of Two No-Zero Integers - Link

Question Description

Given an integer n, return two integers a and b such that a + b == n and neither a nor b contains the digit zero in their decimal representation. You can return any valid pair [a, b].

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Constraints

• 2 <= n <= 10^4

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Approach

We iterate from i = 1 to n - 1. For each i, we check if both i and (n - i) do not contain any zero digit by using the containsZero helper method. As soon as we find such a pair, we return it. The containsZero method checks if a number has the digit 0 by iterating through its digits using modulo and division.

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Dry Run

Example Input: 11

Step-by-step execution:

• Start with i = 1: 1 and 10. 10 contains zero, skip.
• i = 2: 2 and 9. Neither contains zero, return [2, 9].

Final Answer = [2, 9]

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Solution

class Solution {
    public int[] getNoZeroIntegers(int n) {
        for (int i = 1; i < n; i++) {
            if (!containsZero(i) && !containsZero(n - i)) {
                return new int[] { i, n - i };
            }
        }
        return new int[] { 1, n - 1 };
    }

    private boolean containsZero(int num) {
        while (num > 0) {
            int digit = num % 10;
            if (digit == 0) {
                return true;
            }
            num = num / 10;
        }
        return false;
    }
}

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Time and Space Complexity

• Time Complexity: O(n * log(n)) — In the worst case, we iterate up to n and for each number, checking if it contains zero takes O(log n) time (based on the number of digits).
• Space Complexity: O(1) — We only use a constant amount of extra space for variables.

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