HDU 5924 Mr. Frog’s Problem

Mr. Frog’s Problem

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 1504    Accepted Submission(s): 869

Problem Description

One day, you, a clever boy, feel bored in your math class, and then fall asleep without your control. In your dream, you meet Mr. Frog, an elder man. He has a problem for you.

He gives you two positive integers A and B, and your task is to find all pairs of integers (C, D), such that A≤C≤B,A≤D≤B and AB+BA≤CD+DC

 

Input

first line contains only one integer T (T≤125), which indicates the number of test cases. Each test case contains two integers A and B (1≤A≤B≤1018).

 

Output

For each test case, first output one line "Case #x:", where x is the case number (starting from 1). 

Then in a new line, print an integer s indicating the number of pairs you find.

In each of the following s lines, print a pair of integers C and D. pairs should be sorted by C, and then by D in ascending order.

 

Sample Input

210 109 27

 

Sample Output

Case #1:110 10Case #2:29 2727 9

 

Source

2016CCPC东北地区大学生程序设计竞赛 - 重现赛

 

写这道题的时候感觉输出样例有些奇怪，感觉是不是有规律，就写了一发，竟然过了.......

这里有证明：点击打开链接

#include<iostream>using namespace std;typedef long long ll;int main(){int t;cin>>t;for(int i=1;i<=t;i++){ll a,b;cin>>a>>b;printf("Case #%d:\n",i);if(a==b){cout<<1<<endl;cout<<a<<' '<<b<<endl;}else{cout<<2<<endl;cout<<a<<' '<<b<<endl;cout<<b<<' '<<a<<endl;}}}