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 boolean isStrobogrammatic(String num) {
for(int start = 0, end = num.length()-1; start <= end; start++){
switch(num.charAt(start)){
case '0':
case '1':
case '8':
if(num.charAt(end) == num.charAt(start)){
end--;
}else{
return false;
}
break;
case '6':
if(num.charAt(end) == '9'){
end--;
}else{
return false;
}
break;
case '9':
if(num.charAt(end) == '6'){
end--;
}else{
return false;
}
break;
default:
return false;
}
}
return true;
}
