46 lines
755 B
C++
46 lines
755 B
C++
#include <iostream>
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#include <map>
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#include <ctime>
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#include <algorithm>
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using namespace std;
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int a[15],n,m,ans;
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int fun(int num)
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{
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if(num == 0)return 1;
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int sum=1,i;
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for(i=2;i<=num;i++)sum*=i;
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return sum;
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}
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void dfs(int num,int sum,int ma)
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{
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if(sum>m)return ;
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if(num == n)
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{
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if(sum == m)
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{
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ans+=fun(m)/ma;
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}
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return ;
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}
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int i;
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for(i=0;i<=a[num];i++)
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{
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dfs(num+1,sum+i,ma*fun(i));
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}
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}
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int main()
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{
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int i,j;
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while(~scanf("%d %d",&n,&m))
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{
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for(i=0;i<n;i++)
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{
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scanf("%d",&a[i]);
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}
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ans=0;
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dfs(0,0,1);
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printf("%d\n",ans);
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}
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return 0;
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}
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