231110 보행자 천국

public int solution(int m, int n, int[][] cityMap) {
	int[][][] dp = new int[m + 1][n + 1][2];
	final int mod = 20170805;
	dp[0][0][0] = 1;

	for (int i = 0; i < m; i++) {
		for (int j = 0; j < n; j++) {
			switch (cityMap[i][j]) {
				case 0:
					dp[i + 1][j][0] += (dp[i][j][0] + dp[i][j][1]) % mod;
					dp[i][j + 1][1] += (dp[i][j][0] + dp[i][j][1]) % mod;
					break;
				case 2:
					dp[i + 1][j][0] += dp[i][j][0] % mod;
					dp[i][j + 1][1] += dp[i][j][1] % mod;
					break;
				default:
					break;
			}
		}
	}
	return (dp[m - 1][n - 1][0] + dp[m - 1][n - 1][1]) % mod;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/1832