Return the index with the max value. - Java java.util

Java examples for java.util:Map Value

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Description

Return the index with the max value.

Demo Code


//package com.java2s;
import java.util.Collections;

import java.util.Map;

public class Main {
    /** Return the index with the max value. This searches iteratively. If there are multiple max values, then the
     * first one found will be used.//from  w  w w.  j a  va2s  .  co  m
     * @throws java.lang.NullPointerException if input is null.
     * @throws java.lang.IllegalArgumentException if input is empty
     */
    public static <K, V extends Comparable> K getMaxIndex(Map<K, V> nums) {
        if (nums == null) {
            throw new NullPointerException("input must not be null");
        }
        if (nums.isEmpty()) {
            throw new IllegalArgumentException(
                    "input must have at least one value");
        }

        Comparable maxValue = Collections.max(nums.values());
        for (Map.Entry<K, V> entry : nums.entrySet()) {
            if (entry.getValue().compareTo(maxValue) == 0) {
                return entry.getKey();
            }
        }
        throw new IllegalArgumentException("case not handled");
    }
}

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