240822 RGB거리 2

public static void main(String[] args) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

	int n = Integer.parseInt(br.readLine());
	int[][] dp = new int[n][3];
	int[][] house = new int[n][3];

	for (int i = 0; i < n; i++) {
		StringTokenizer st = new StringTokenizer(br.readLine(), " ");
		for (int j = 0; j < 3; j++) {
			house[i][j] = Integer.parseInt(st.nextToken());
		}
	}

	int answer = 1000002;

	for (int firstColor = 0; firstColor < 3; firstColor++) {
		for (int color = 0; color < 3; color++) {
			dp[n - 1][color] = (color == firstColor) ? 1000001 : house[n - 1][color];
		}

		for (int i = n - 2; i > 0; i--) {
			dp[i][0] = Math.min(dp[i + 1][1], dp[i + 1][2]) + house[i][0];
			dp[i][1] = Math.min(dp[i + 1][0], dp[i + 1][2]) + house[i][1];
			dp[i][2] = Math.min(dp[i + 1][0], dp[i + 1][1]) + house[i][2];
		}

		for (int color = 0; color < 3; color++) {
			if (firstColor != color) {
				answer = Math.min(answer, house[0][firstColor] + dp[1][color]);
			}
		}
	}

	bw.write(String.valueOf(answer));
	bw.flush();
	bw.close();
	br.close();
}

출처:https://www.acmicpc.net/problem/17404