Map-1

mapBully

public Map<String, String> mapBully(Map<String, String> map) {
  if (map.containsKey("a")) {
    map.put("b", map.get("a"));
    map.put("a", "");
  }
  return map;
}

mapShare

public Map<String, String> mapShare(Map<String, String> map) {
  if (map.containsKey("c")) map.remove("c");
  if (map.containsKey("a")) {
    map.put("b", map.get("a"));
  }
  return map;
}

mapAB

public Map<String, String> mapAB(Map<String, String> map) {
  if (map.containsKey("a") && map.containsKey("b")) {
    map.put("ab", map.get("a") + map.get("b"));
  }
  return map;
}

topping1

public Map<String, String> topping1(Map<String, String> map) {
  map.put("bread", "butter");
  if (map.containsKey("ice cream")) map.put("ice cream", "cherry");
  return map;
}

topping2

public Map<String, String> topping2(Map<String, String> map) {
  if (map.containsKey("ice cream")) map.put("yogurt", map.get("ice cream"));
  if (map.containsKey("spinach")) map.put("spinach", "nuts");

  return map;
}

topping3

public Map<String, String> topping3(Map<String, String> map) {
  if (map.containsKey("potato")) map.put("fries", map.get("potato"));
  if (map.containsKey("salad")) map.put("spinach", map.get("salad"));
  return map;
}

mapAB2

• 문자열 비교할 때 equals() 주의하자

public Map<String, String> mapAB2(Map<String, String> map) {
  if (map.containsKey("a") && map.containsKey("b")) {
    if (map.get("a").equals(map.get("b"))) {
      map.remove("a");
      map.remove("b");
    }
  }
  return map;
}

mapAB3

public Map<String, String> mapAB3(Map<String, String> map) {
  if (map.containsKey("a") && map.containsKey("b")) return map;
  if (map.containsKey("a")) map.put("b", map.get("a"));
  if (map.containsKey("b")) map.put("a", map.get("b"));
  return map;
}

mapAB4

public Map<String, String> mapAB4(Map<String, String> map) {
  if (map.containsKey("a") && map.containsKey("b")) {
    int a = map.get("a").length();
    int b = map.get("b").length();
    
    if (a == b) {
      map.put("a", "");
      map.put("b", "");
    }
    else if (a > b) map.put("c", map.get("a"));
    else map.put("c", map.get("b"));
  }

  return map;
}