剑指 Offer 57. 和为s的两个数字

public int[] twoSum(int[] nums, int target) {
        int len = nums.length;
        if(len==1) 
            if(target == nums[0]) return nums;
            else return new int[0];
        int i = 0,j = len-1;
        while (i<j){
            int x = nums[i] + nums[j];
            if(x>target) j--;
            else if(x<target) i++;
            else return new int[]{nums[i],nums[j]};
        }
        return new int[0];
    }