LeetCode Daily Temperatures

typedef int* Stack; // just a fancier name for an array

class Solution {
public:
    vector<int> dailyTemperatures(vector<int>& temperatures) {
     const int N = temperatures.size();
        vector<int> sol(N,0);
        Stack stack_top = (Stack) alloca(sizeof(int) * (N-1));
        Stack stack_base = stack_top;
        for(long i = 0; i < N - 1;++i)
        {
            if(temperatures[i] < temperatures[i+1])
            {
                sol[i] = 1;
                 while(stack_base != stack_top && temperatures[*(stack_top-1)] < temperatures[i+1])
                {
                    sol[*(stack_top -1 )] = i + 1 - *(stack_top - 1);

                    if( stack_base != stack_top) --stack_top;
                }
            }
            else
            {
                *stack_top++ = i;
            }
        }
        return sol;
    }
};