Strobogrammatic Number

Strobogrammatic Number hash table

A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down).

Write a function to determine if a number is strobogrammatic. The number is represented as a string.

For example, the numbers “69”, “88”, and “818” are all strobogrammatic.

public class StrobogrammaticNumber {
    public boolean isStrobogrammatic(String num) {
        for(int i = 0, j = num.length() - 1; i <= j; i++, j--) {
            if(!"00 11 88 696".contains(num.charAt(i) + "" + num.charAt(j))) {
                return false;
            }
        }

        return true;
    }
}

Last modified October 4, 2020