[백준] 20291번 파일정리

import java.util.Scanner;
import java.util.TreeMap;
public class Main {
	
	public static void main(String[] args){
		
		Scanner kb = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		
		TreeMap<String, Integer> map = new TreeMap<>();
		
		int n = kb.nextInt();
		
		for(int i=0; i<n; i++) {
			String[] fileName = kb.next().split("\\.");
			map.put(fileName[1], map.getOrDefault(fileName[1], 0)+1);
		}
		
		for(String x: map.keySet()) {
			sb.append(x+" "+ map.get(x)+"\n");
		}
		
		System.out.println(sb.toString());

	}
}