PAT甲级1048 Find Coins （25 分）（二分）

1048 Find Coins （25 分）

Eva loves to collect coins from all over the universe, including some other planets like Mars. One day she visited a universal shopping mall which could accept all kinds of coins as payments. However, there was a special requirement of the payment: for each bill, she could only use exactly two coins to pay the exact amount. Since she has as many as 10​5​​ coins with her, she definitely needs your help. You are supposed to tell her, for any given amount of money, whether or not she can find two coins to pay for it.

Input Specification:

Each input file contains one test case. For each case, the first line contains 2 positive numbers: N (≤10​5​​, the total number of coins) and M (≤10​3​​, the amount of money Eva has to pay). The second line contains N face values of the coins, which are all positive numbers no more than 500. All the numbers in a line are separated by a space.

Output Specification:

For each test case, print in one line the two face values V​1​​ and V​2​​ (separated by a space) such that V​1​​+V​2​​=M and V​1​​≤V​2​​. If such a solution is not unique, output the one with the smallest V​1​​. If there is no solution, output No Solution instead.

Sample Input 1:

8 15
1 2 8 7 2 4 11 15

Sample Output 1:

4 11

Sample Input 2:

7 14
1 8 7 2 4 11 15

Sample Output 2:

No Solution

//题意：给出n个数，如存在一组数v1,v2，使得v1+v2=m，则输出v1,v2，若有多组，则输出v1最小的那组；

//思路：二分

//读成输出下标最小的v1,且index (v1)

//二分查找时，若没有符合要求的数，low=n，对应测试点倒数第二个

#include
#include
#include
#include
#include
using namespace std;
int n,m;
int a[100005];
int main()
{
    scanf("%d%d",&n,&m);
    for(int i=0;i