Leetcode – paint house I solution (Java)

Tags: , ,

Paint House I
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.

Analysis

We can use Dynamic programming to solve this problem.

Define DP[i][j] as the minimum cost to paint house until i with color j. where i  ∈ [1, n]  and j ∈ {0, 1, 2}.

We can reuse the costs array. Here is the implementation: