p1428 [NOIP2011提高组day2]-1-计算系数

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题目

https://www.luogu.org/problemnew/show/P1313

代码

#include<bits/stdc++.h>
using namespace std;
const int mod=10007;
const int _=1500;
inline int read()
{
	int f=1,num=0;
	char ch=getchar();
	while (ch<'0'||ch>'9') { if (ch=='-') f=-1; ch=getchar(); }
	while (ch>='0'&&ch<='9') num=(num<<1)+(num<<3)+ch-'0', ch=getchar();
	return num*f;
}
int c[_][_];
inline int coe(int x,int y)//coefficient 系数 
{
	if (!y) return 1;
	long long cnt=1;
	for (register int i=1;i<=y;++i)
		cnt*=x,cnt%=mod;
	return cnt;
}
int main()
{
	int a=read(),b=read(),k=read(),n=read(),m=read();
	memset(c,0,sizeof(c));
	c[0][0]=1;
	for (register int i=1;i<=k;++i)
	{
		c[i][0]=c[i][i]=1;
		for (register int j=1;j<i;++j)
			c[i][j]=(c[i-1][j]%mod+c[i-1][j-1]%mod)%mod;
	}
	long long ans=c[k][m]*(coe(a,n)*coe(b,m)%mod)%mod;
	printf("%lld\n",ans);
	return 0;
}