Leetcode 256: Paint House

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.

Note:
All costs are positive integers.

 

public class Solution {
    public int MinCost(int[,] costs) {
        int dpRed = 0, dpBlue = 0, dpGreen = 0;
        
        for (int i = 0; i < costs.GetLength(0); i++)
        {
            int tRed = dpRed, tBlue = dpBlue, tGreen = dpGreen;
                
            dpRed = Math.Min(tBlue, tGreen) + costs[i, 0];
            dpBlue = Math.Min(tRed, tGreen) + costs[i, 1];
            dpGreen = Math.Min(tRed, tBlue) + costs[i, 2];
        }
        
        return Math.Min(dpRed, Math.Min(dpBlue, dpGreen));
    }
}