P2532 [AHOI2012] 树屋阶梯

#include<bits/stdc++.h>
using namespace std;
int f[550][500], l = 1;
void add(int u) {
	for (int i = 1; i <= l; i ++ )
		f[u][i] = f[u - 1][i] + f[u][i];
	for (int i = 1; i <= l; i ++ )
		f[u][i + 1] += f[u][i] / 10,
		f[u][i] %= 10;
	if (f[u][l + 1]) l ++ ;
}
int main() {
	int n, p;
	cin >> n;
	f[1][1] = 1;
	for (int i = 2; i <= n + 1; i ++ )
		for (int j = 1; j <= i; j ++ )
			add(j);
	for (int i = l; i > 0; i -- )
		cout << f[n][i];
}