Leetcode 1056. Confusing Number

Given a number N, return true if and only if it is a confusing number, which satisfies the following condition:

We can rotate digits by 180 degrees to form new digits. When 0, 1, 6, 8, 9 are rotated 180 degrees, they become 0, 1, 9, 8, 6 respectively. When 2, 3, 4, 5 and 7 are rotated 180 degrees, they become invalid. A confusing number is a number that when rotated 180 degrees becomes a different number with each digit valid.

Clarification:

Example 1:

Input: 6
Output: true
Explanation: 
We get 9 after rotating 6, 9 is a valid number and 9!=6.

Example 2:

Input: 89
Output: true
Explanation: 
We get 68 after rotating 89, 86 is a valid number and 86!=89.

Example 3:

Input: 11
Output: false
Explanation: 
We get 11 after rotating 11, 11 is a valid number but the value remains the same, thus 11 is not a confusing number.

Example 4:

Input: 25
Output: false
Explanation: 
We get an invalid number after rotating 25.

Assumption:

1. 0 <= N <= 10^9
2. After the rotation we can ignore leading zeros, for example if after rotation we have 0008 then this number is considered as just 8.

Result: As below.

Test: As below.

class Solution {
    public boolean confusingNumber(int N) {
        Map<Integer, Integer> map = new HashMap<>();
        map.put(6, 9);
        map.put(9, 6);
        map.put(0, 0);
        map.put(1, 1);
        map.put(8, 8);
        
        int newNum = 0;
        int tmp = N;
        while (tmp != 0) {
            if (!map.containsKey(tmp % 10)) {
                return false;
            }
            newNum = 10 * newNum + map.get(tmp % 10);
            tmp /= 10;
        }
        return N == newNum ? false : true;
    }
}