Leetcode 256. Paint House (Medium) (cpp)

Leetcode 256. Paint House (Medium) (cpp)

Tag: Dynamic Programming

Difficulty: Medium

/*

256. Paint House (Medium)

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.

*/
class Solution {
public:
	int minCost(vector<vector<int>>& costs) {
		if (costs.size() == 0 || costs[0].size() == 0) {
			return 0;
		}
		for (int i = 1; i < costs.size(); i++) {
			for (int j = 0; j < 3; j++) {
				if (j == 0) {
					costs[i][0] += min(costs[i - 1][1], costs[i - 1][2]);
				}
				else if (j == 1) {
					costs[i][1] += min(costs[i - 1][0], costs[i - 1][2]);
				}
				else {
					costs[i][2] += min(costs[i - 1][0], costs[i - 1][1]);
				}
			}
		}
		return min(costs.back()[0], min(costs.back()[1], costs.back()[2]));
	}
};