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;
  }
}