2541. Sum Of Number And Its Reverse¶

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2541. Sum of Number and Its Reverse

Medium

Given a non-negative integer num, return true if num can be expressed as the sum of any non-negative integer and its reverse, or false otherwise.

Example 1:

Input: num = 443
Output: true
Explanation: 172 + 271 = 443 so we return true.

Example 2:

Input: num = 63
Output: false
Explanation: 63 cannot be expressed as the sum of a non-negative integer and its reverse so we return false.

Example 3:

Input: num = 181
Output: true
Explanation: 140 + 041 = 181 so we return true. Note that when a number is reversed, there may be leading zeros.

Constraints:

• 0 <= num <= 105

Solution¶

class Solution {
    public boolean sumOfNumberAndReverse(int num) {
        for (int i = num / 2; i <= num; i++) {
            if (i + get(i) == num) return true;
        }
        return false;
    }
    private int get(int n) {
        int res = 0;
        while (n > 0) {
            res = res * 10 + n % 10;
            n /= 10;
        }
        return res;
    }
}

Complexity Analysis¶

• Time Complexity: O(?)
• Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here