백준 2579 c++

#include <iostream>
#include <algorithm>

using namespace std;

int input(int lower, int upper)
{
	//cout << "input()" << endl;
	int A;

	while (1)
	{
		cin >> A;
		if (A >= lower && A <= upper)
		{
			break;
		}
		else
		{
			;
		}
	}

	return A;
}

void input_stair(int* stair, int n)
{
	//cout << "input_stair()\n";
	int i;

	for (i = 1; i <= n; i++)
	{
		stair[i] = input(1, 10000);
	}

	return;
}

int find_result(int* stair, int n)
{
	//cout << "find_result()";
	int i;
	int* result = new int[n+3];//버퍼 오버런 : n값이 1,2일경우 n+1이 3이 되지 못할 수 있음 
	int maximum;
	
	result[0] = stair[0];
	result[1] = stair[0] + stair[1];
	result[2] = stair[0] + stair[1] + stair[2];
	result[3] = max(stair[2] + stair[3],  stair[1] + stair[3]);
	for (i = 4; i <= n; i++)
	{
		result[i] = max(result[i-3] + stair[i-1], result[i-2]) + stair[i];
	}	
	maximum = result[n];
	delete[] result;

	return maximum;
}

int main(void)
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int* stair;
	int n;

	n = input(1, 300);
	stair = new int[n + 1] {0};
	input_stair(stair, n);
	cout << find_result(stair, n) << "\n";
	delete[] stair;

	return 0;
}