和为s的两个数字

Posted 2020-11-21 樱圃

题目一：输入一个递增排序的数组和一个数字s，在数组中查找两个数，使得它们的和正好是s。如果有多对数字的和等于s，输出任意一对即可。

import java.util.*;
public class FindSumNumber{
    public ArrayList<Integer> getSumNumber(int[] array,int sum){
    
        if(array == null || array.length == 0 || sum <= 2) return null;
        int num1 = 0;
        int num2 = 0;
        int head = 0;
        int end = array.length-1;
        ArrayList<Integer> list = new ArrayList<Integer>();
        while(head < end){
            int temp = array[head]+array[end];
            if(temp == sum){
                num1 = array[head];
                num2 = array[end];
                break;
            }
            else if(temp<sum){
                head++;
            }else{
                end--;
            }
            
        }
        if(head < end){
            list.add(num1);
            list.add(num2);
        }
        return list;
    }
    public static void main(String[] args){
        int[] array = {1,2,4,7,11,15};
        FindSumNumber f = new FindSumNumber();
        ArrayList<Integer> list = f.getSumNumber(array,16);
        Iterator<Integer> iter = list.iterator();
        while(iter.hasNext()){
            System.out.println(iter.next());
        }
    }
}