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.
*/
// This method is so far the cleanest I have seen. Copied from others.
public int minCost(vector< vector<int> >& costs) {
  if(costs.size() == 0 || costs[0].size() == 0) return 0;
  int min_red = costs[0][0];
  int min_blue = costs[0][1];
  int min_green = costs[0][2];
  int tmp_red, tmp_blue, tmp_green;
  for(int i = 1; i < costs.size(); ++i) {
    tmp_red = min_red;
    tmp_blue = min_blue;
    tmp_green = min_green;
    min_red = min(tmp_blue, tmp_green) + costs[i][0];
    min_blue = min(tmp_red, tmp_green) + costs[i][1];
    min_green = min(tmp_blue, tmp_red) + costs[i][2];
  }
  return min(min_red, min(min_blue, min_green));
}