Java - 求数组中最大值（个数不确定）及其下标

利用 Map，遍历一次即可获得数组中最大值的同时，也获得最大值的数组下标。

package com.code.ggsddu;
 
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
 
public class ArrayMaxAndIndexes {
    public static void main(String[] args) {
        int[] arr0 = {2, 2, 2, 2, 2};
        int[] arr1 = {2, 3, 5, 4, 3};
        int[] arr2 = {3, 3, 5, 5, 5};
        int[] arr3 = {1, 2, 3, 5, 5};
        int[] arr4 = {5, 4, 2, 5, 5};
        System.out.println(Arrays.toString(arr0));
        getMaxValuesAndIndexes(arr0);
        System.out.println("--------------------");
        System.out.println(Arrays.toString(arr1));
        getMaxValuesAndIndexes(arr1);
        System.out.println("--------------------");
        System.out.println(Arrays.toString(arr2));
        getMaxValuesAndIndexes(arr2);
        System.out.println("--------------------");
        System.out.println(Arrays.toString(arr3));
        getMaxValuesAndIndexes(arr3);
        System.out.println("--------------------");
        System.out.println(Arrays.toString(arr4));
        getMaxValuesAndIndexes(arr4);
    }
 
    public static void getMaxValuesAndIndexes(int[] arr) {
        Map<String, Object> map = new HashMap<>();
        int max = arr[0];
        map.put("indexes", 0);
        for (int i = 1; i < arr.length; i++) {
            int temp = arr[i];
            if (max == temp) {
                map.put("indexes", map.get("indexes") + "," + i);
            } else if (max < temp) {
                max = temp;
                map.put("indexes", i);
            }
        }
        System.out.println("max: " + max);
        System.out.println("indexes: " + map.get("indexes"));
        String[] indexesArray = map.get("indexes").toString().split(",");
        System.out.println("indexesArray: " + Arrays.toString(indexesArray));
    }
}

控制台打印结果：

[2, 2, 2, 2, 2]
max: 2
indexes: 0,1,2,3,4
indexesArray: [0, 1, 2, 3, 4]
--------------------
[2, 3, 5, 4, 3]
max: 5
indexes: 2
indexesArray: [2]
--------------------
[3, 3, 5, 5, 5]
max: 5
indexes: 2,3,4
indexesArray: [2, 3, 4]
--------------------
[1, 2, 3, 5, 5]
max: 5
indexes: 3,4
indexesArray: [3, 4]
--------------------
[5, 4, 2, 5, 5]
max: 5
indexes: 0,3,4
indexesArray: [0, 3, 4]
 
Process finished with exit code 0