LeetCode 1056. Confusing Number Solution in Java, C++, Python & More | Explanation + Code

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

PythonJavaC++GoPHP

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(code-box)

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; } }(code-box)

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; } };(code-box)

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 }(code-box)

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; } }(code-box)