递推求组合数模板

const LL MAX = (LL)1e15 + 100;
const int MAX_INDEX = 1001;
LL f[MAX_INDEX][MAX_INDEX];

void init()
{
    FF(i, 1, MAX_INDEX)
    {
        f[i][0] = f[i][i] = 1;
        FF(j, 1, i)
        {
            f[i][j] = f[i - 1][j] + f[i - 1][j - 1];
            if (f[i][j] > MAX) f[i][j] = MAX;
        }
    }
}