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https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
58 lines
1.2 KiB
C++
58 lines
1.2 KiB
C++
#include<iostream>
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#include<string.h>
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using namespace std;
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#define MAXN 150
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#define MOD 20090829
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__int64 dp[MAXN][MAXN],c[MAXN][MAXN];
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__int64 a[MAXN];
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__int64 b[MAXN];
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int gcd(int x,int y)
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{
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if (y==0) return x;
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else return gcd(y,x%y);
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}
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__int64 C(int k,int n)
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{
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int i,j;
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if (c[k][n]!=0) return c[k][n];
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__int64 temp,ans;
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for(i=n-k+1;i<=n;i++) a[i]=i;
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for(i=1;i<=k;i++) b[i]=i;
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for(i=1;i<=k;i++)
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for(j=n-k+1;j<=n;j++)
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{
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temp=gcd(b[i],a[j]);
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b[i]/=temp;
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a[j]/=temp;
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}
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ans=1;
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for(i=n-k+1;i<=n;i++)
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ans=ans*a[i]%MOD;
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c[k][n]=ans;
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return ans;
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}
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int min(int x,int y)
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{
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if (x<y) return x;
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else return y;
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}
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int main()
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{
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int n,d,i,j,k;
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__int64 ans;
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memset(c,0,sizeof(c));
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while(scanf("%d %d",&n,&d)!=EOF)
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{
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memset(dp,0,sizeof(dp));
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dp[0][0]=1;
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for(i=1;i<=n;i++)
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for(j=0;j<=n-2;j++)
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for(k=0;k<=min(j,d-1);k++)
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{
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dp[i][j]=(dp[i][j]+dp[i-1][j-k]*C(k,n-2-(j-k)))%MOD;
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}
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ans=dp[n][n-2];
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printf("%I64d\n",ans);
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}
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}
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