uva_cpp_clean/10007/10007-21.cpp

/*
  >>~~ UVa Online Judge ACM Problem Solution ~~<<

  ID: 10007
  Name: Count the Trees
  Problem: https://onlinejudge.org/external/100/10007.pdf
  Language: C++

  Author: Arash Shakery
  Email: [email protected]
*/

#include <bits/stdc++.h>
using namespace std;

class BigInt {
    typedef int CellType;
    const static int CellSize = sizeof(CellType);
    const static int MAX_C = 10000;
    const static int MAX_D = 4;
    CellType *cells;
    int capacity, size, sign;

    int sgn(int x) {
        return x<0 ? -1 : x>0 ? 1 : 0;
    }

    int countDigits(int x) {
        if (!x) return 0;
        if (x < 0) x = -x;
        return floor(log10(x)) + 1;
    }

    void init() {
        sign = size = 0;
        cells = new CellType[capacity = 4];
        memset(cells, 0, 4*CellSize);
    }

    int setSize(int sz, bool cp = true) {
        if (sz > capacity) {
            CellType* ncells = new CellType[capacity = sz + 16];
            if (cp && size)
                memcpy(ncells, cells, size*CellSize);

            if (cells) delete [] cells;
            cells = ncells;
        }
        if (!cp)
             memset(cells, 0, capacity*CellSize);
        else memset(cells+sz, 0, (capacity-sz)*CellSize);
        return size = sz;
    }

    BigInt& autoSize() {
        while (size>0 && !cells[size-1])
            size--;
        if (!size) sign=0;
        return *this;
    }

    // ---------------------------------------------------------------------

    public:
    BigInt() { init(); }
    BigInt(int x) {
        init();
        setTo(x);
    }

    BigInt(const char s[]) {
        while (s[0]==' ' || s[0]=='\n' || s[0]=='\t') s++;
        sign = 1;
        if (s[0] == '+') s++;
        if (s[0] == '-') { sign=-1; s++; }
        while (s[0]=='0') s++;
        if (!s[0]) { init(); return; }

        int len = strlen(s);
        size = (len+3)/MAX_D;
        cells = new CellType[capacity = size+16];
        for (int i=len-1; i>=0; i-=MAX_D) {
            int rc = 0;
            for (int k=i-MAX_D+1; k<=i; k++) {
                if (k<0 || s[k]=='-' || s[k]=='+') continue;
                rc = rc*10 + s[k] - '0';
            }
            cells[(len-i-1) / MAX_D] = rc;
        }
        for (int i=size; i<capacity; i++) cells[i] = 0;
        autoSize();
    }

    BigInt(const BigInt& o): cells(0), capacity(0) {
        sign = o.sign;
        setSize(o.size, 0);
        for (int i=0; i<size; i++)
            cells[i] = o.cells[i];
    }

    ~BigInt() {
        if (capacity >= 0)
            delete [] cells;
    }

    int getSize() { return size; }
    int getCell(int i) { return cells[i]; }
    bool isZero() { return !sign; }
    BigInt& setOne() { sign=size=cells[0]=1; return *this; }
    BigInt& setTo(int x) {
        sign = sgn(x); x*=sign;
        for (size=0; x; size++) {
            cells[size] = x % MAX_C;
            x /= MAX_C;
        }
        return *this;
    }
    // ---------------------------------------------------------------------
    private:
    bool numLess(const BigInt &o) const {
        if (size != o.size)
            return size < o.size;
        for (int i=size-1; i>=0; i--)
            if (cells[i] != o.cells[i])
                return cells[i] < o.cells[i];
        return false;
    }
    bool numEq(const BigInt &o) const {
        if (size!=o.size)
            return false;
        for (int i=size-1; i>=0; i--)
            if (cells[i] != o.cells[i])
                return false;
        return true;
    }

    public:
    bool operator <  (const BigInt &o) const {
        return sign==o.sign ? (sign>0 ? numLess(o) : o.numLess(*this)) : sign < o.sign;
    }
    bool operator == (const BigInt &o) const { return sign==o.sign && numEq(o); }
    bool operator != (const BigInt &o) const { return !(*this == o); }
    bool operator <= (const BigInt &o) const { return !(o  < *this); }
    bool operator >  (const BigInt &o) const { return  (o  < *this); }
    bool operator >= (const BigInt &o) const { return !(*this <  o); }
    // ---------------------------------------------------------------------
    BigInt& operator=(const BigInt& o) {
        if ((sign = o.sign)) {
            setSize(o.size, 0);
            memcpy(cells, o.cells, o.size*CellSize);
        }
        else size=0;
        return *this;
    }

    BigInt& operator+= (BigInt o) {
        if (!o.sign) return *this;
        if (!sign) sign = o.sign;
        if (sign != o.sign) {
            o.sign *= -1;
            operator-=(o);
            o.sign *= -1;
            return *this;
        }

        int osz = size;
        setSize(max(size, o.size)+1);
        for (int i=osz; i<o.size+1; i++)
            cells[i] = 0;

        for (int i=0; i<size; i++) {
            if (i < o.size)
                cells[i] += o.cells[i];
            if (cells[i] >= MAX_C) {
                cells[i] -= MAX_C;
                ++cells[i+1];
            }
        }
        return autoSize();
    }
    BigInt& operator+= (int x) { return *this += *new BigInt(x); } //TODO: optimize
    BigInt operator+ (int x) const { return *new BigInt(*this) += x; }
    BigInt operator+ (BigInt& o) const { return *new BigInt(*this) += o; }

    // ---------------------------------------------------------------------

    BigInt& operator-= (BigInt& o) {
        if (!o.sign) return *this;
        if (!sign) sign = -o.sign;
        if (sign != o.sign) {
            o.sign *= -1;
            operator+=(o);
            o.sign *= -1;
            return *this;
        }

        if (*this == o) {
            sign = size = 0;
            return *this;
        }
        if (!o.numLess(*this))
            return *this = -(o - *this);

        for (int i=0; i<size; i++) {
            if (i < o.size)
                cells[i] -= o.cells[i];
            if (cells[i] < 0) {
                cells[i] += MAX_C;
                --cells[i+1];
            }
        }
        return autoSize();
    }
    BigInt& operator-= (int x) { return *this -= *new BigInt(x); }
    BigInt operator- (int x) const { return *new BigInt(*this) -= x; }
    BigInt operator- (BigInt& o) const { return *new BigInt(*this) -= o; }
    BigInt operator-() { BigInt tmp(*this); tmp.sign *= -1; return tmp; }

    // ---------------------------------------------------------------------

    BigInt& operator*= (int x) {
        if (x > 10000) {
            return *this *= BigInt(x);
        }

        sign *= sgn(x);
        if (!sign) {
            size = 0;
            return *this;
        }
        if (x<0) x = -x;

        int cr = 0;
        for (int i=0; i < size; i++) {
            cells[i] = cells[i] * x + cr;
            cr = cells[i] / MAX_C;
            cells[i] %= MAX_C;
        }

        if (cr) {
            int ex = (countDigits(cr)+MAX_D-1)/MAX_D, sz=size;
            setSize(size + ex);
            size = sz;
            for (; cr; cr /= MAX_C)
                cells[size++] = cr % MAX_C;
        }

        return autoSize();
    }
    BigInt operator* (const BigInt &o) const {
        if (sign*o.sign == 0)
            return *new BigInt(0);
        if (o.size == 1)
            return *new BigInt(*this) *= o.cells[0];

        BigInt r(sign*o.sign);
        r.setSize(size + o.size + 1, 0);
        for (int i=0; i<size; i++)
            for (int j=0; j<o.size; j++) {
                r.cells[i+j] += cells[i]*o.cells[j];
                r.cells[i+j+1] += r.cells[i+j] / MAX_C;
                r.cells[i+j] %= MAX_C;
            }
        return r.autoSize();
    }
    BigInt& operator*= (const BigInt &o) {
        if (!(sign *= o.sign)) {
            size = 0;
            return *this;
        }
        if (o.size == 1)
            return *this *= o.cells[0];
        return *this = *this * o;
    }
    BigInt operator* (int x) const { return *new BigInt(*this) *= x; }

    // ---------------------------------------------------------------------

    BigInt& operator/= (long long den) {
        if (!den) den/=den;
        long long t = 0;
        for (int i=size-1; i>=0; --i) {
            t = t*MAX_C + cells[i];
            cells[i] = t / den;
            t -= (long long) cells[i] * den;
        }
        return autoSize();
    }
    BigInt operator/ (int den) const { return *new BigInt(*this) /= den; }

    int operator% (int den) const {
        int r = 0;
        for (int i = size-1; i>=0; --i)
            r = (r * MAX_C + cells[i]) % den;
        return r;
    }

    // ---------------------------------------------------------------------
    friend std::ostream& operator<< (std::ostream& stream, const BigInt& bs) {
        if (!bs.sign)
            stream << 0;
        else {
            if (bs.sign < 0) stream << '-';
            stream << bs.cells[bs.size-1];
            for (int i=bs.size-2; i>=0; i--)
                stream << setfill('0') << setw(MAX_D) << bs.cells[i];
        }
        return stream;
    }
};
BigInt operator*(int m, BigInt &n) { return n * m; }
BigInt operator+(int m, BigInt &n) { return n + m; }
BigInt operator-(int m, BigInt &n) { return -n + m; }

// ----------------------------------------------------------------------------------

int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);

    BigInt F[313];
    F[0].setOne();
    F[1].setOne();
    for (int i=2; i<301; ++i)
        F[i] = F[i-1] * i;

    BigInt C[313];
    C[0].setOne();
    for (int i=1; i<313; ++i) {
        C[i]  = C[i-1];
        C[i] *= 4*i-2;
        C[i] /= i+1;
    }

    int n;
    while (cin >> n && n)
        cout << C[n] * F[n] << endl;
}