代码

typedef unsigned u32;
    u32 solve(int n, char *s)
    {
        int *pool = new int[2 * n + 3];
        memset(pool, 0, sizeof(int) * (2 * n + 3));
        pool += n;
        int *const start = pool;
        *pool = 1;
        for(int i = 1; i <= n; i++)
        {
            int len = std::min(i, n - i);
            if(s[i - 1] == '(')
                --pool;
            else if(s[i - 1] == ')')
                ++pool;
            else for(int j = (i & 1); j <= len; j += 2)
                    pool[j] = pool[j - 1] + pool[j + 1];
            pool[-1] = 0;
        }
        return *pool;
    }
f

评测结果