import java.util.ArrayList;

import java.util.List;

public class StringIterator

{

String expandedString = "";

List<Integer> list = new ArrayList<>();

int pos = 0;

public StringIterator( String compressedString )

{

int i = 0, j = 0;

StringBuilder sb = new StringBuilder();

while ( i < compressedString.length() )

{

while ( j < compressedString.length() && !( compressedString.charAt( j ) <= '9' && compressedString.charAt( j ) >= '0' ) )

j++;

String s = compressedString.substring( i, j );

expandedString += s;

i = j;

while ( j < compressedString.length() && compressedString.charAt( j ) <= '9' && compressedString.charAt( j ) >= '0' )

j++;

int val = Integer.valueOf( compressedString.substring( i, j ) );

i = j;

list.add( val );

}

}

public char next()

{

if ( hasNext() )

{

list.set( pos, list.get( pos ) - 1 );

char c = expandedString.charAt( pos );

if ( list.get( pos ) <= 0 )

pos++;

return c;

}

else

return ' ';

}

public boolean hasNext()

{

if ( pos < list.size() && list.get( pos ) > 0 )

return true;

return false;

}

public static void main( String[] args )

{

StringIterator s = new StringIterator( "L1e2t1C1o1d1e1" );

String[] op = { "StringIterator", "next", "next", "next", "next", "next", "next", "hasNext", "next", "hasNext" };

// {{"a1234567890b1234567890"},{},{},{},{},{},{},{},{},{}};

for ( int i = 1; i < op.length; i++ )

{

if ( op[i].equals( "next" ) )

System.out.println( s.next() );

else

System.out.println( s.hasNext() );

}

// {{"L1e2t1C1o1d1e1"},{},{},{},{},{},{},{},{},{}};

}

}