백준 1149 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_RGBarr(int** cost, int size)
{
	//cout << "input_RGBarr()\n";
	int i, j;

	cost[0][0] = 0;
	cost[0][1] = 0;
	cost[0][2] = 0;
	for (i = 1; i <= size; i++)
	{
		for (j = 0; j < 3; j++)
		{
			cost[i][j] = input(1, 1000);
		}
	}

	return;
}

int find_result(int** cost, int size)
{
	//cout << "find_result()\n";
	int i;

	for (i = 1; i <= size; i++)
	{
		//R을 선택한 경우
		cost[i][0] = cost[i][0] + min(cost[i - 1][1], cost[i - 1][2]);
		//G를 선택한 경우
		cost[i][1] = cost[i][1] + min(cost[i - 1][0], cost[i - 1][2]);
		//B를 선택한 경우
		cost[i][2] = cost[i][2] + min(cost[i - 1][0], cost[i - 1][1]);
	}

	return min(cost[size][0], min(cost[size][1], cost[size][2]));
}

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

	int N, i;
	int **cost;

	N = input(2, 1000);
	cost = new int* [N+1];
	for (i = 0; i <= N; i++)
	{
		cost[i] = new int[3];
	}
	input_RGBarr(cost, N);
	cout << find_result(cost, N) << "\n";
	for (i = 0; i <= N; i++)
	{
		delete[] cost[i];
	}
	delete[] cost;

	return 0;
}