# 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

• 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;
}
}

• 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;
}
};

• 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


• 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
}

• 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;
}
}