42.和为S的两个数字

import java.util.ArrayList;
public class Solution {
    public ArrayList<Integer> FindNumbersWithSum(int [] array,int sum) {
        ArrayList<Integer> res=new ArrayList<>();
        if(array==null || array.length<2){
            return res;
        }
        int start=0,end=array.length-1;
        while(start<end){
            int cursum=array[start]+array[end];
            if(cursum==sum){
                res.add(array[start]);
                res.add(array[end]);
                return res;
            }else if(cursum<sum){
                start++;
            }else{
                end--;
            }
        }
        return res;
    }
}