Problem:
Book Index

Books are indexed. Write a program which reads a list of pairs of a word and a page number, and prints the word and a list of the corresponding page numbers.

You can assume that a word consists of at most 30 characters, and the page number is less than or equal to 1000. The number of pairs of a word and a page number is less than or equal to 100. A word never appear in a page more than once.

The words should be printed in alphabetical order and the page numbers should be printed in ascending order.

Input

word page_number
:
:

Output

word
a_list_of_the_page_number
word
a_list_of_the_Page_number
:
:

Sample Input

style 12
even 25
introduction 3
easy 9
style 7
document 13
style 21
even 18

Output for the Sample Input

document
13
easy
9
even
18 25
introduction
3
style
7 12 21

Solution in JAVA (judge verdict: Accepted)

import java.util.*;class Main{public static void main(String[]z){Map<String,Map<Integer,Long>>m=new TreeMap<String,Map<Integer,Long>>();String k;for(Scanner s=new Scanner(System.in);s.hasNext();m.get(k).put(s.nextInt(),0L))if(!m.containsKey(k=s.next()))m.put(k,new TreeMap<Integer,Long>());k="";for(String x:m.keySet()){k+=x+"\n";for(int i:m.get(x).keySet())k+=i+" ";k=k.replaceAll(" $","\n");}System.out.print(k);}}