[qqwref]

You can do it character by character - it's actually not that bad since you are just reading positive integers.

int[] guesses = (array of zeroes); // this user's guesses
int guessnum = 0; // start from the first guessed number

for(character in string starting from the first '[')
{
 if (character == ',' || character == ']') { // go to next guessed number
  guessnum++;
 } else if (character >= '0' && character <= '9') {
  guesses[guessnum] = 10*guesses[guessnum] + (character - '0');
 }
}