有序数组的两数和

public class DoublePointer {
    public static void main(String[] args){
        int[] arr = {2,3,5,8,9,12,15,21};
        int target = 20;
        print(twoSum(arr, target));
    }

    public static int[] twoSum(int[] arr, int target) {
        int i = 0, j = arr.length - 1;
        while (i < j) {
            int sum = arr[i] + arr[j];
            if (sum == target) {
                return new int[]{i + 1, j + 1};
            } else if (sum < target) {
                i++;
            } else {
                j--;
            }
        }
        return null;
    }

    public static void print(int[] arr){
        System.out.print("[");
        for (int i = 0; i < arr.length; i++){
            if (i!=arr.length-1){
                System.out.print(arr[i] + ",");
            }else{
                System.out.print(arr[i]);
            }

        }
        System.out.print("]");
    }
}