public class StringIterator {

private final String str;

private char curChar;

private int curCharCount;

private int nextId;

public StringIterator(String compressedString) {

this.str = compressedString;

nextId = 0;

moveToNextAvailable();

}

private void moveToNextAvailable() {

for (; curCharCount == 0 && nextId < str.length();) {

curChar = str.charAt(nextId++);

for(; nextId < str.length() && Character.isDigit(str.charAt(nextId)); nextId++) {

int d = str.charAt(nextId) - '0';

curCharCount = 10 * curCharCount + d;

}

}

}

public char next() {

if (!hasNext()) {

return ' ';

}

char ret = curChar;

curCharCount--;

if (curCharCount == 0) {

moveToNextAvailable();

}

return ret;

}

public boolean hasNext() {

return curCharCount > 0;

}

}

/**

* Your StringIterator object will be instantiated and called as such:

* StringIterator obj = new StringIterator(compressedString);

* char param_1 = obj.next();

* boolean param_2 = obj.hasNext();

*/