Paths on a Grid（规律）

最新推荐文章于 2025-05-21 09:11:05 发布

weixin_34112181

最新推荐文章于 2025-05-21 09:11:05 发布

阅读量128

点赞数

Paths on a Grid

Time Limit: 1000MS		Memory Limit: 30000K
Total Submissions: 23270		Accepted: 5735

Description

Imagine you are attending your math lesson at school. Once again, you are bored because your teacher tells things that you already mastered years ago (this time he's explaining that (a+b) ²=a ²+2ab+b ²). So you decide to waste your time with drawing modern art instead.

Fortunately you have a piece of squared paper and you choose a rectangle of size n*m on the paper. Let's call this rectangle together with the lines it contains a grid. Starting at the lower left corner of the grid, you move your pencil to the upper right corner, taking care that it stays on the lines and moves only to the right or up. The result is shown on the left:

Really a masterpiece, isn't it? Repeating the procedure one more time, you arrive with the picture shown on the right. Now you wonder: how many different works of art can you produce?

Input

The input contains several testcases. Each is specified by two unsigned 32-bit integers n and m, denoting the size of the rectangle. As you can observe, the number of lines of the corresponding grid is one more in each dimension. Input is terminated by n=m=0.

Output

For each test case output on a line the number of different art works that can be generated using the procedure described above. That is, how many paths are there on a grid where each step of the path consists of moving one unit to the right or one unit up? You may safely assume that this number fits into a 32-bit unsigned integer.

Sample Input

5 4
1 1
0 0

Sample Output

126
2
题解：找规律，总共走了m+n步，从这m+n步中选m步向右，规律很容易找出来，但是却是无符号的32位；
代码：

 1 #include<stdio.h>
 2 #include<math.h>
 3 const int MAXN=100010;
 4 int main(){
 5     __int64 N,ans;
 6     int T;
 7     scanf("%d",&T);
 8     while(T--){
 9         ans=0;
10         scanf("%I64d",&N);
11         N++;
12         int flot=0;
13         for(int i=2;i<=sqrt(N);i++)if(N%i==0)ans++;
14         printf("%I64d\n",ans);
15     }
16     return 0;
17 }