Java查找不重复无序数组中是否存在两个数字的和为某个值

public class getTwoNumsSumEquals {  public static void main(String[] args) {    int[] arr = new int[]{3, 4, 6, 5, 9, 8};    int num = 8;    int[] ret = getIndex(arr, num);    System.out.println("index of two numbers R:" + ret[0] + " " + ret[1]);  }  // 找到这两个数的下标并返回（以长度为2的数组的形式返回）  private static int[] getIndex(int[] arr, int num) {    int[] ret = new int[2];    HashMap<Integer, Integer> hashMap = new HashMap<>();    int index = 0;    // 将每个数字和其下标放进map中    for (Integer curr : arr) {      hashMap.put(curr, index++);    }   // 遍历HashMap并判断    for (Map.Entry<Integer, Integer> entry : hashMap.entrySet()) {      int value = entry.getKey();      int subValue = num - value;      if(hashMap.containsKey(subValue)) {        // 找到啦!        ret[0] = entry.getValue();        ret[1] = hashMap.get(subValue);        break;      }    }    return ret;  }}