392B


  Posted on 19 Dec 2014
dynamic programming

Solution


#include <cstdio>
#include <algorithm>
using namespace std;

const int MAX_N = 50;

int cost[3][3];
long long f[MAX_N][3][3];
int n;

int main()
{
	//input
	for (int i = 0; i < 3; i++)
		for (int j = 0; j < 3; j++)
			scanf("%d", &cost[i][j]);
	scanf("%d", &n);
	//work
	for (int i = 1; i <= n; i++)
	{
		for (int j = 0; j < 3; j++)
		{
			for (int k = 0; k < 3; k++)
			{
				if (j == k)
					continue;
				int x = 3 - j - k;
				f[i][j][k] = f[i - 1][j][x] + cost[j][k] + f[i - 1][x][k];
				f[i][j][k] = min(f[i][j][k], f[i - 1][j][k] + cost[j][x] + f[i - 1][k][j] + cost[x][k] + f[i - 1][j][k]);
			}
		}
	}
	printf("%I64d\n", f[n][0][2]);
	return 0;
}