import java.util.HashMap;

import java.util.Map;

/**

* Created by pm-01 on 03.02.2017.

*/

public class Map1 {

public static void main(String[] args) {

/*

mapBully({"b": "dirt", "a": "candy"}) > {"b": "candy", "a": ""}

mapBully({"a": "candy"}) > {"b": "candy", "a": ""}

mapBully({"b": "carrot", "c": "meh", "a": "candy"}) > {"b": "candy", "c": "meh", "a": ""}

*/

//Map<String, String> map = new HashMap<String, String>();

//Map<String, Integer> map = new HashMap<String, Integer>();

Map<String, Boolean> map = new HashMap<String, Boolean>();

//"salad": "oil", "potato": "ketchup"

//map.put("salad", "oil");

//map.put("potato", "ketchup");

//map.put("c", "meh");

String[] strArray = new String[]{"ax", "bx", "ay", "by", "ai", "aj", "bx", "by"};

String[] strArrayOut = new String[strArray.length];

Map1 map1 = new Map1();

strArrayOut = map1.allSwap(strArray);

//System.out.println(result);

String div = "";

for (int i = 0; i < strArrayOut.length; i++) {

System.out.print(div + strArrayOut[i]);

div = ", ";

}

System.out.println();

/*

for (Map.Entry<String, Boolean> pair : map.entrySet()) {

String key = pair.getKey(); //ключ

Boolean value = pair.getValue(); //значение

System.out.println(key + ":" + value);

}

*/

}

public String[] allSwap(String[] strings) {

Map<String, Integer> map = new HashMap<String, Integer>();

for (int i = 0; i < strings.length; i++) {

String firstChar = new String(strings[i].substring(0, 1));

if (map.containsKey(firstChar)) {

if (map.get(firstChar) != -1) {

String helpStr = strings[i];

strings[i] = strings[map.get(firstChar)];

strings[map.get(firstChar)] = helpStr;

map.put(firstChar, -1);

}

}

else {

map.put(firstChar, i);

}

}

return strings;

}

/*

public Map<String, String> mapBully(Map<String, String> map) {

if (map.containsKey("potato")) {

String value = map.get("potato");

map.put("fries", value);

}

if (map.containsKey("salad")) {

String value = map.get("salad");

map.put("spinach", value);

}

return map;

}

*/

}