CodeVs 3150 (大数 + 递推）

来源：互联网发布：萧然网络问政瓜沥编辑：程序博客网时间：2024/06/15 23:28
#include<iostream>#include<cstdio>#include<cstring>#include<string>#include<cmath>#include<algorithm>#include<map>#include<set>#include<vector>#include<queue>#include<stack>//#include<bits/std c++.h>using namespace std;typedef long long LL;typedef unsigned long long ULL;const LL MOD = 1e7 + 7;const LL maxn = 1e6 + 131;const LL Bits = 1e10;const double Pi = acos(-1.0);struct BigInt{    vector<LL> val;    void Set(LL n) { val.clear(); val.push_back(n); }    void operator += (const BigInt a)    {        int i;        for(i = 0; i < val.size() && i < a.val.size() ; ++i)            val[i] = val[i] + a.val[i];        if(i < a.val.size()) for(; i < a.val.size(); ++i) val.push_back(a.val[i]);        int len = val.size();        for(i = 0; i < len; ++i)        {            if(val[i] >= Bits)            {                if(i == len-1) val.push_back(val[i]/Bits), val[i] %= Bits;                else {                    val[i+1] += (val[i] / Bits);                    val[i] %= Bits;                }            }        }    }    void operator *= (const LL k)    {        int i;        for(i = 0; i < val.size(); ++i) val[i] *= k;        i = 0;        while(i != val.size())        {            if(val[i] >= Bits)            {                if(i == val.size() -1)                {                    val.push_back(val[i] / Bits);                    val[i] %= Bits;                }                else                {                    val[i+1] += (val[i] / Bits);                    val[i]   %= Bits;                }            }            ++i;        }    }    void operator /= (const LL k)    {        for(int i = val.size() - 1; i >= 1; --i)        {            val[i-1] += (val[i] % k)*Bits;            val[i] /= k;        }        val[0] /= k;        int i = val.size() - 1;        while(val.size() > 1)        {            if(val[i] == 0) val.erase(--val.end());            else break;            i--;        }    }    void Show()    {        cout << val[val.size() - 1];        for(int i = val.size() - 2; i >= 0 ; --i)        {            LL k = Bits / 10;            while( k > 1 )            {                if(val[i] < k) cout << "0";                k /= 10;            }            cout << val[i];        }        cout << endl;    }};int main(){    BigInt A, B;    LL n;    /*A.Set(1), B.Set(Bits - 1);    A += B;    A.Show();*/    //cout << Pi << endl;    while(cin >> n){    if(n < 4) cout << "1\n";    else {        n -= 4;        A.Set(1), B.Set(1);        LL i = 1, j = (n + Pi), Last;        while(i <= (LL)((n + Pi)/ Pi))        {            Last = j;            j = (n + Pi - i*Pi);            for(LL k = Last - 1; k >= j + 1; k--)            {                B *= (k+1);                B /= (i + k);            }            B *= (j + 1);            B /= i;            i ++;            A += B;        }        A.Show();    }    }    return 0;}
0 0