poj2084

//卡特兰数的应用: h(n) = (4n-2)/(n+1) * h(n-1) (n>1), h(0)=1
//poj2084
#include
#include
using namespace std;

void mul(int a[],int b) {//b为乘数
int tmp = 0;
for (int i = 99; i >= 5 ; i–) {//没有倒回来存,注意留出一些位放进位
tmp += a[i] * b;//依次进位
a[i] = tmp%10;
tmp /= 10;
}
return;
}

void div(int a[],int b) {//b为除数
int tmp = 0;
for (int i = 0; i <= 99; ++i) {
tmp = a[i] + 10*tmp;
a[i] = tmp/b;
tmp %= b;
}
return;
}

int main() {
int a[101][100];
int n,count;
fill(a[1],a[1]+100,0);
a[1][99] = 1;
for (int i = 2; i <= 100; i++) {
memcpy(a[i],a[i-1],100sizeof(int));
mul(a[i],4i-2);
div(a[i],i+1);
}
while (cin >> n && n != -1) {
for (int i = 0; i <= 99; i++) {
if (a[n][i]) {
count = i;
//cout << count << endl;
break;
}
}
for (int i = count; i <= 99; i++) {
cout << a[n][i];
}
cout << endl;
}
return 0;
}