94 lines
1.7 KiB
C++
94 lines
1.7 KiB
C++
#include <iostream>
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#include <vector>
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#include <list>
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#include <deque>
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#include <queue>
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#include <iterator>
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#include <stack>
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#include <map>
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#include <set>
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#include <algorithm>
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#include <cctype>
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#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <string>
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#include <cmath>
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using namespace std;
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const int N=10001;
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typedef long long LL;
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int su[N],num[N];
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int n,m,sui;
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void mul(LL &res,int k)
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{
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for(int i=0;i<sui;i++)
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{
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while(k%su[i]==0)
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{
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k/=su[i];
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num[i]++;
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}
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}
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res=(res*k)%m;
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}
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int ext_gcd(int a,int b,int &x,int &y)
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{
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int t,ret;
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if(!b)
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{
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x=1;y=0;return a;
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}
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ret=ext_gcd(b,a%b,y,x);
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y-=x*(a/b);
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return ret;
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}
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void chu(LL &res,int k)
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{
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for(int i=0;i<sui;i++)
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{
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while(k%su[i]==0&&num[i]>0)
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{
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k/=su[i];
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num[i]--;
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}
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}
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if(k!=1)
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{
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int x,y,temp;
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temp=ext_gcd(k,m,x,y);
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x=(x%m+m)%m;
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res=(res*x)%m;
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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,k,t;
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while(scanf("%d%d",&n,&m)&&(n+m))
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{
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sui=0,t=m;
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for(i=2;i*i<=t;i++)
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if(t%i==0)
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{
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su[sui++]=i;
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while(t%i==0)
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t/=i;
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}
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if(t>1)
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su[sui++]=t;
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memset(num,0,sizeof(num));
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LL res=1,sum=1,l;
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for(i=2;i<=n;i++)
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{
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mul(res,4*i-2);
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chu(res,i+1);
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l=res;
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for(j=0;j<sui;j++)
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for(k=0;k<num[j];k++)
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l=l*su[j]%m;
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sum=(sum+l)%m;
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}
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printf("%lld\n",sum);
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}
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return 0;
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}
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