_1056.java

package com.fishercoder.solutions;

import java.util.HashMap;
import java.util.Map;

/**
 * 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.
 *
 * 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.
 *
 *  Note:
 *
 * 0 <= N <= 10^9
 * After the rotation we can ignore leading zeros, for example if after rotation we have 0008 then this number is considered as just 8.*/
public class _1056 {
    public static class Solution1 {
        Map<Integer, Integer> map = new HashMap<Integer, Integer>() {{
            put(0, 0);
            put(1, 1);
            put(8, 8);
            put(6, 9);
            put(9, 6);
        }
        };

        public boolean confusingNumber(int N) {
            if (N == 0) {
                return false;
            }
            int newNumber = 0;
            int originalN = N;
            while (N != 0) {
                newNumber *= 10;
                int digit = N % 10;
                if (!map.containsKey(digit)) {
                    return false;
                }
                digit = map.get(digit);
                newNumber += digit;
                N /= 10;
            }
            return newNumber != originalN;
        }
    }
}