Obtaining key associated with corresponding maximum value in a Map(TreeMap/HashMap)

Question

I have written the below code to find out the key(String) that has the maximum value(Integer) using TreeMap in JAVA.

public static void maxprofitItem(int[] costs         


        

Answer 1

You seem to be asking if using TreeMap instead of HashMap will give you a simpler way to find the key corresponding to the largest value/

The answer to that is ... unfortunately ... No.

Answer 2

The trick is that you can find maximum value together with its key by providing Comparator that compares entries by value.

Comparator<Map.Entry<String, Integer>> byValue = Map.Entry.comparingByValue();
Map.Entry<String, Integer> maxEntry = Collections.max(map.entrySet(), byValue);
System.out.println("Maximum value is " + maxEntry.getValue());
System.out.println("And it is for " + maxEntry.getKey());

Or using new stream API

map.entrySet().stream()
    .max(Map.Entry.comparingByValue())
    .ifPresent(maxEntry -> {
        System.out.println("Maximum value is " + maxEntry.getValue());
        System.out.println("And it is for " + maxEntry.getKey());
    });