Im having trouble understanding two lines of code in this solution to the question: Implement an algorithm to determine if a string has all unique characters.

The part that I dont understand is: if(char_set[val]) {

return false;

}

char_set[val] = true;

Can anyone please explain the code to me? Id really appreciate it

The code below implements this algorithm. 1 boolean isUniqueChars (String str) ( 2 if (str.length() 128) return false; 4 boolean[] char_set - new boolean[128]; for (int 0; ?