1048. Find coins (25)-pat

1048. Find coins (25) Time Limit 50 ms memory limit 32000 kb code length limit 16000 B discriminant program standard author Chen, Yue

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 cocould accept all kinds of coins as payments. however, there was a special requirement of the payment: For each
Bill, she cocould only use exactly two coins to pay the exact amount. Since she has as same 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 (<= 103, 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 V2 (separated by a space) such that V1 + V2 = m and V1 <=
V2. If such a solution is not unique, output the one with the smallest v1. If there is no solution, output "no solution" instead.}

Sample input 1:

8 151 2 8 7 2 4 11 15

Sample output 1:

4 11

Sample input 2:

7 141 8 7 2 4 11 15

Sample Output 2:

No Solution

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Source: http://pat.zju.edu.cn/contests/pat-a-practise/1048

The beauty of thinking and programming "2.12 quick search for two numbers that meet the conditions" is the same

#include<iostream>#include<stdio.h>#include<stdlib.h>int compare_int(const void * a, const void *b){return (*((int*)a)-*((int *)b));}using namespace std;int main(){int low,high;int n,m,i;cin>>n>>m;int *coins=new int[n];for(i=0;i<n;i++)cin>>coins[i];qsort(coins,n,sizeof(int),compare_int);low=0;high=n-1;do{int tmp=coins[low]+coins[high];if(tmp==m){cout<<coins[low]<<" "<<coins[high]<<endl;break;}else if(tmp>m)high--;elselow++;}while(low<=high-1);if(low>high-1)cout<<"No Solution"<<endl;return 0;}