1056. Confusing Number

Description

A confusing number is a number that when rotated 180 degrees becomes a different number with each digit valid.

We can rotate digits of a number by 180 degrees to form new digits.

  • When 0, 1, 6, 8, and 9 are rotated 180 degrees, they become 0, 1, 9, 8, and 6 respectively.
  • When 2, 3, 4, 5, and 7 are rotated 180 degrees, they become invalid.

Note that after rotating a number, we can ignore leading zeros.

  • For example, after rotating 8000, we have 0008 which is considered as just 8.

Given an integer n, return true if it is a confusing number, or false otherwise.

 

Example 1:

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

Example 2:

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

Example 3:

Input: n = 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

 

Constraints:

  • 0 <= n <= 109

Solutions

Solution 1

Python Code
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class Solution:
    def confusingNumber(self, n: int) -> bool:
        x, y = n, 0
        d = [0, 1, -1, -1, -1, -1, 9, -1, 8, 6]
        while x:
            x, v = divmod(x, 10)
            if d[v] < 0:
                return False
            y = y * 10 + d[v]
        return y != n

Java Code
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class Solution {
    public boolean confusingNumber(int n) {
        int[] d = new int[] {0, 1, -1, -1, -1, -1, 9, -1, 8, 6};
        int x = n, y = 0;
        while (x > 0) {
            int v = x % 10;
            if (d[v] < 0) {
                return false;
            }
            y = y * 10 + d[v];
            x /= 10;
        }
        return y != n;
    }
}

C++ Code
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class Solution {
public:
    bool confusingNumber(int n) {
        vector<int> d = {0, 1, -1, -1, -1, -1, 9, -1, 8, 6};
        int x = n, y = 0;
        while (x) {
            int v = x % 10;
            if (d[v] < 0) {
                return false;
            }
            y = y * 10 + d[v];
            x /= 10;
        }
        return y != n;
    }
};

Go Code
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func confusingNumber(n int) bool {
	d := []int{0, 1, -1, -1, -1, -1, 9, -1, 8, 6}
	x, y := n, 0
	for x > 0 {
		v := x % 10
		if d[v] < 0 {
			return false
		}
		y = y*10 + d[v]
		x /= 10
	}
	return y != n
}

PHP Code
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class Solution {
    /**
     * @param Integer $n
     * @return Boolean
     */
    function confusingNumber($n) {
        $d = [0, 1, -1, -1, -1, -1, 9, -1, 8, 6];
        $x = $n;
        $y = 0;
        while ($x > 0) {
            $v = $x % 10;
            if ($d[$v] < 0) {
                return false;
            }
            $y = $y * 10 + $d[$v];
            $x = intval($x / 10);
        }
        return $y != $n;
    }
}