256 Paint House

There is a row of n houses, where each house can be painted one of 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 an n x 3 cost matrix costs.

• For example, costs[0][0] is the cost of painting house 0 with the color red; costs[1][2] is the cost of painting house 1 with color green, and so on...

Return the minimum cost to paint all houses.

Example 1:

Input: costs = [[17,2,17],[16,16,5],[14,3,19]]
Output: 10
Explanation: Paint house 0 into blue, paint house 1 into green,
paint house 2 into blue.
Minimum cost: 2 + 5 + 3 = 10.

Example 2:

Input: costs = [[7,6,2]]
Output: 2

Constraints:

• costs.length == n
• costs[i].length == 3
• 1 <= n <= 100
• 1 <= costs[i][j] <= 20

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class Solution:
    def minCost(self, costs: List[List[int]]) -> int:
        r, b, g = costs[0]
        for i in range(1, len(costs)):
            cur_r, cur_b, cur_g = costs[i]
            r, b, g = (
                min(g, b) + cur_r,
                min(r, g) + cur_b,
                min(r, b) + cur_g,
            )
        return min(r, b, g)