hdoj：2067

根据公式计算卡特兰数，始终出现越界，自己无法解决

#include <iostream>

using namespace std;

long long Catalan(int num)
{
    long long result = ;
    for (int i = ; i <= num; i++)
        result *= (i + num);
    for (int i = ; i <= num; i++)
        result /= i;
    result /= (num + );
    return (long long)result;
}
int main()
{
    int num;
    int i = ;
    while (cin >> num && num != -)
    {
        printf("%d %d %I64d\n", i++, num,  * Catalan(num));

    }
}

根据递推公式

动态规划

#include <iostream>

using namespace std;

long long dp[][];
int main()
{

    int num;

    int i = ;
    for (int i = ; i <= ; i++)
        dp[i][] = ;
    for (int i = ; i <= ; i++)
    {
        for (int j = ; j <= i; j++)
        {
            if (i == j)
                dp[i][j] = dp[i][j - ];
            else
                dp[i][j] = dp[i - ][j] + dp[i][j - ];
        }
    }
    while (cin >> num && num != -)
    {
        printf("%d %d %I64d\n", i++, num,  * dp[num][num]);

    }
}