1.1 Is Unique: Implement an algorithm to determine if a string has all unique characters.What if you cannot use additional data structures?
Assuming all characters are ASCII.
public static boolean isUniqueChars(String str) {
if (str.length() > 256) {
return false;
}
int checker = 0;
for (int i = 0; i < str.length(); i++) {
int val = str.charAt(i) - 'a';
if ((checker & (1 << val)) > 0) return false;
checker |= (1 << val);
}
return true;
}
Or just use a boolean array of size 256 to check duplicate.
