Paint House leetcode

There are a row of n houses, each house can be painted with one of the three colors: red, blue or green. The cost of painting each house with a certain color is different. You have to paint all the houses such that no two adjacent houses have the same color.

The cost of painting each house with a certain color is represented by a n x 3 cost matrix. For example, costs[0][0] is the cost of painting house 0 with color red;costs[1][2] is the cost of painting house 1 with color green, and so on... Find the minimum cost to paint all houses.

public class Solution {
    public int minCost(int[][] costs) {
        if(costs == null || costs.length == 0 || costs[0] == null || costs[0].length == 0) {
            return 0;
        }
        int n = costs.length;
        int[][] dp = new int[n][3];
        for (int i = 0; i < 3; i++) {
            dp[0][i] = costs[0][i];
        }
        for (int j = 1; j < costs.length; j++) {
            dp[j][0] = costs[j][0] + Math.min(dp[j - 1][1], dp[j - 1][2]);
            dp[j][1] = costs[j][1] + Math.min(dp[j - 1][0], dp[j - 1][2]);
            dp[j][2] = costs[j][2] + Math.min(dp[j - 1][1], dp[j - 1][0]);
        }
        return Math.min(dp[n - 1][0], Math.min(dp[n - 1][1], dp[n - 1][2]));

    }
}