CodeForces - 4C

题目链接
思路：map储存字符串以及字符串出现的次数

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        Map<String,Integer> map = new HashMap<>();
        while((n--)>0){
            String t = sc.next();
            if(!map.containsKey(t)){
                System.out.println("OK");
                map.put(t,1);
            }
            else{
              int u = map.get(t);
              map.put(t,u+1);
              map.put(t+u,1);
              System.out.println(t+u);
            }
        }
    }
}