要点：
使用Map辅助存储

代码：
import java.util.HashMap;
import java.util.Map;

public class FindTwoNum {
    public static void main(String[] args) {
        int[] arr = {2, 1, 4, 6, 7, 9, 4, 5, 6, 1, 0};
        findTwoSum(arr, 1);
        findTwoSum(arr, 16);
    }

    static void findTwoNum(int[] arr, int t) {
        Map<Integer, Integer> map = new HashMap<>();
        int n;
        for (int i = 0; i < arr.length; i++) {
            n = t - arr[i];
            if (!map.containsKey(n)) {
                map.put(arr[i], i);
            } else {
                System.out.println("i1= " + i + ", i2= " + map.get(n));
                break;
            }
        }
    }
}