125 lines
2.1 KiB
C++
125 lines
2.1 KiB
C++
// luogu-judger-enable-o2
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#include<vector>
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#include<cstdio>
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#include<queue>
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#include<string>
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#include<cstring>
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#include<algorithm>
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#include<cmath>
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int CacheSize=10;//try to use the cache
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struct BigInt
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{
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bool f;
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std::vector<int> num;
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static const int base=100000000;
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BigInt()
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{
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f=0;
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num.push_back(0);
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}
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void format()
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{
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while(num.size()>1&&num[num.size()-1]==0) num.erase(num.end()-1);
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if(num.size()==1&&num[0]==0) f=0;
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}
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//Input and Output
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char* c_str()
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{
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char *p;
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p=new char[num.size()*8+16];
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memset(p,0,sizeof(p));
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if(f) sprintf(p,"-");
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sprintf(p,"%s%d",p,num[num.size()-1]);
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for(int i=num.size()-2;i>=0;i--) sprintf(p,"%s%08d",p,num[i]);
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return p;
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}
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BigInt operator=(int v)
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{
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f=0;
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if(v<0)
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{
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f=1;
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v=-v;
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}
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std::queue<int> q;
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if(v==0) q.push(0);
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else
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while(v>0)
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{
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q.push(v%base);
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v/=base;
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}
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num.resize(q.size());
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for(int i=0;q.size()>0;i++)
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{
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num[i]=q.front();
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q.pop();
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}
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return *this;
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}
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BigInt operator+(BigInt& b)
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{
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format();
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b.format();
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BigInt c;
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int t=0,t2=std::max(num.size(),b.num.size())+1;
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c.num.resize(t2);
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memset(&c.num[0],0,t2*4);
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for(int i=0;i<t2;i++)
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{
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if(i<num.size()) t+=num[i];
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if(i<b.num.size()) t+=b.num[i];
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c.num[i]=t%base;
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t/=base;
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}
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c.format();
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return c;
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}
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BigInt operator*(BigInt& b)
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{
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format();
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b.format();
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BigInt c;
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c.num.resize(num.size()+b.num.size());
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memset(&c.num[0],0,(num.size()+b.num.size())*4);
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int i,j,k,I,J;
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long long t;
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for(i=0;i*CacheSize<num.size();i++)
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for(j=0;j*CacheSize<b.num.size();j++)
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for(I=i*CacheSize;I<(i+1)*CacheSize&&I<num.size();I++)
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for(J=j*CacheSize;J<(j+1)*CacheSize&&J<b.num.size();J++)
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{
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t=(long long)num[I]*b.num[J];
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t+=c.num[I+J];
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c.num[I+J]=t%base;
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k=I+J+1;
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t/=base;
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while(t>0)
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{
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t+=c.num[k];
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c.num[k++]=t%base;
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t/=base;
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}
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}
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c.f=(f!=b.f);
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c.format();
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return c;
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}
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};
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using namespace std;
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int main()
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{
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BigInt res,t,t2;
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t=1;
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int n;
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scanf("%d",&n);
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for(int i=1;i<=n;i++)
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{
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t2=i;
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t=t*t2;
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res=res+t;
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}
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printf("%s\n",res.c_str());
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return 0;
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}
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