ACM 威士忌部分答案
源代码在线查看： 1023 train problem ii.cpp
//和Problem: 1130 ( How Many Trees? ) 相同, 1134 Game of Connections , 1023 Train Problem II
//求二叉树计数
//C(2n,n)-C(2n,n-1)=C(2n,n) / (n+1)
#include
#include
#include
#include
using namespace std;
#define MAXN 9999
#define DLEN 4
class BigNum{
private:
int a[300];//DLEN digs for a position
int len;
public:
BigNum(){len = 1;memset(a,0,sizeof(a));}
BigNum(const int b);
BigNum(const BigNum & T);
bool Bigger(const BigNum &) const;
BigNum & operator=(const BigNum &);
BigNum & Add(const BigNum &);
BigNum & Sub(const BigNum &);
BigNum operator+(const BigNum &) const;
BigNum operator-(const BigNum &) const;
BigNum operator*(const BigNum &) const;
BigNum operator/(const int &) const;
void Print();
BigNum operator+=(const BigNum &) ;
BigNum operator-=(const BigNum &) ;
BigNum operator*=(const BigNum &) ;
BigNum operator/=(const int &) ;
};
BigNum::BigNum(const int b)
{
int c,d = b;
len = 0;
memset(a,0,sizeof(a));
while(d > MAXN){
c = d - d / (MAXN + 1) * (MAXN + 1);
d = d / (MAXN + 1);
a[len++] = c;
}
a[len++] = d;
}
BigNum::BigNum(const BigNum & T) : len(T.len)
{
int i;
memset(a,0,sizeof(a));
for(i = 0 ; i < len ; i++)
a[i] = T.a[i];
}
bool BigNum::Bigger(const BigNum & T) const
{
int ln;
if(len > T.len) return true;
else if(len == T.len){
ln = len - 1;
while(a[ln] == T.a[ln] && ln >= 0) ln--;
if(ln >= 0 && a[ln] > T.a[ln]) return true;
else return false;
}
else return false;
}
BigNum & BigNum::operator=(const BigNum & n)
{
len = n.len;
memset(a,0,sizeof(a));
for(int i = 0 ; i < len ; i++)
a[i] = n.a[i];
return *this;
}
BigNum & BigNum::Add(const BigNum & T)
{
int i,big;
big = T.len > len ? T.len : len;
for(i = 0 ; i < big ; i++)
{
a[i] = a[i] + T.a[i];
if(a[i] > MAXN)
{
a[i + 1]++;
a[i] = a[i] - MAXN - 1;
}
}
if(a[big] != 0) len = big + 1;
else len = big;
return *this;
}
BigNum & BigNum::Sub(const BigNum & T)
{
int i,j,big;
big = T.len > len ? T.len : len;
for(i = 0 ; i < big ; i++){
if(a[i] < T.a[i]){
j = i + 1;
while(a[j] == 0) j++;
a[j--]--;
while(j > i) a[j--] += MAXN;
a[i] = a[i] + MAXN + 1 - T.a[i];
}
else a[i] -= T.a[i];
}
len = big;
while(a[len - 1] == 0 && len > 1) len--;
return *this;
}
BigNum BigNum::operator+(const BigNum & n) const
{
BigNum a = *this;
a.Add(n);
return a;
}
BigNum BigNum::operator-(const BigNum & T) const
{
BigNum b = *this;
b.Sub(T);
return b;
}
BigNum BigNum::operator*(const BigNum & T) const
{
BigNum ret;
int i,j,up;
int temp,temp1;
for(i = 0 ; i < len ; i++){
up = 0;
for(j = 0 ; j < T.len ; j++){
temp = a[i] * T.a[j] + ret.a[i + j] + up;
if(temp > MAXN){
temp1 = temp - temp / (MAXN + 1) * (MAXN + 1);
up = temp / (MAXN + 1);
ret.a[i + j] = temp1;
}
else {
up = 0;
ret.a[i + j] = temp;
}
}
if(up != 0)
ret.a[i + j] = up;
}
ret.len = i + j;
while(ret.a[ret.len - 1] == 0 && ret.len > 1) ret.len--;
return ret;
}
BigNum BigNum::operator/(const int & b) const
{
BigNum ret;
int i,down = 0;
for(i = len - 1 ; i >= 0 ; i--){
ret.a[i] = (a[i] + down * (MAXN + 1)) / b;
down = a[i] + down * (MAXN + 1) - ret.a[i] * b;
}
ret.len = len;
while(ret.a[ret.len - 1] == 0) ret.len--;
return ret;
}
void BigNum::Print()
{
int i;
cout for(i = len - 2 ; i >= 0 ; i--){
cout.width(DLEN);
cout.fill('0');
cout }
cout }
BigNum BigNum::operator*=(const BigNum & T)
{
BigNum ret;
int i,j,up;
int temp,temp1;
for(i = 0 ; i < len ; i++){
up = 0;
for(j = 0 ; j < T.len ; j++){
temp = a[i] * T.a[j] + ret.a[i + j] + up;
if(temp > MAXN){
temp1 = temp - temp / (MAXN + 1) * (MAXN + 1);
up = temp / (MAXN + 1);
ret.a[i + j] = temp1;
}
else {
up = 0;
ret.a[i + j] = temp;
}
}
if(up != 0)
ret.a[i + j] = up;
}
ret.len = i + j;
while(ret.a[ret.len - 1] == 0 && ret.len > 1) ret.len--;
*this=ret;
return ret;
}
BigNum BigNum::operator/=(const int & b)
{
BigNum ret;
int i,down = 0;
for(i = len - 1 ; i >= 0 ; i--){
ret.a[i] = (a[i] + down * (MAXN + 1)) / b;
down = a[i] + down * (MAXN + 1) - ret.a[i] * b;
}
ret.len = len;
while(ret.a[ret.len - 1] == 0) ret.len--;
*this=ret;
return ret;
}
const int Max=100;
int main()
{
int t,n,ca;
BigNum ans;
while(cin>>n)
{
if(n==-1)
break;
for(ca=2*n,ans=1;ca>=n+2;ca--)
{
ans*=ca;
}
for(ca=2;ca {
ans/=ca;
}
ans.Print();
}
return 0;
}
