Find the no of Occurrences in a List without using a Inner Loop

FindTheDuplicatesWithoutInnerLoop.java

package interviewprograms;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class FindTheDuplicates {

	public static void main(String args[]) {
		List<String> cityList=new ArrayList<>();
		cityList.add("Chennai");
		cityList.add("Mumbai");
		cityList.add("Chennai");
		cityList.add("Kolkatta");
		cityList.add("Madurai");
		cityList.add("Chennai");
		cityList.add("Mumbai");

		Set<String> citySet=new HashSet<>(cityList);
		Map<String,Integer> cityMap=new HashMap<>();
		for(String city:citySet) {
			cityMap.put(city, 0);
		}
		
		for(String city:cityList) {
			cityMap.put(city,cityMap.get(city)+1);
		}
		System.out.println(cityMap);
		
		
	}
}