锐客网

  1. 首页 > it技术 > >

Hdu3037 Saving Beans Lucas定理

数论

Description
Although winter is far away, squirrels have to work day and night to save beans. They need plenty of food to get through those long cold days. After some time the squirrel family thinks that they have to solve a problem. They suppose that they will save beans in n different trees. However, since the food is not sufficient nowadays, they will get no more than m beans. They want to know that how many ways there are to save no more than m beans (they are the same) in n trees.

Now they turn to you for help, you should give them the answer. The result may be extremely huge; you should output the result modulo p, because squirrels can’t recognize large numbers.

Input
The first line contains one integer T, means the number of cases.

Then followed T lines, each line contains three integers n, m, p, means that squirrels will save no more than m same beans in n different trees, 1 <= n, m <= 1000000000, 1 < p < 100000 and p is guaranteed to be a prime.

Output
You should output the answer modulo p.

Sample Input
2
1 2 5
2 1 5

Sample Output
3

3


题意：将m个物体放到n个不同的盒子中，允许不装满，问有多少种可能？
可以假设有n+1个盒子，第n+1个盒子装剩余的物体，那么由隔板法可得结果为C 【n+m】【m】，

再用下Lucas定理即可。

#include #include #include #include #include #include #include using namespace std; #define LL long long #define maxn 100005 LL f[maxn]; void init(LL p) { LL i; f[0]=1; for(i=1; i<=p; i++){ f[i]=f[i-1]*i%p; } } LL powmod(LL a,LL b,LL p) { LL res=1; while(b!=0){ if(b&1) res=(res*a)%p; a=(a*a)%p; b>>=1; } return res; }LL Lucas(LL n,LL m,LL p) { LL ans=1; while(n&&m){ LL nn=n%p,mm=m%p; if(nn



【Hdu3037 Saving Beans Lucas定理】

    推荐阅读


    上一篇：JavaScript BOM操作 使用window对象 → 打开和关闭窗口（open() / close() 方法）

    下一篇：miniUI datagrid打开行内编辑时，下拉框控件显示的是id而不是text解决