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.
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| public class Solution {
public boolean isStrobogrammatic(String num) {
for (int i = 0; i <= num.length() / 2; i++) {
char a = num.charAt(i);
char b = num.charAt(num.length() - 1 - i);
if (!isValid(a, b)) {
return false;
}
}
return true;
}
private boolean isValid(char c, char b) {
switch (c) {
case '1':
return b == '1';
case '6':
return b == '9';
case '9':
return b == '6';
case '8':
return b == '8';
case '0':
return b == '0';
default:
return false;
}
}
}
|