1 class Solution {
2 public:
3 /*
4 * @param costs: n x 3 cost matrix
5 * @return: An integer, the minimum cost to paint all houses
6 */
7 const int inf = 0x3f3f3f3f;
8 vector<vector<int> > dp;
9 int minCost(vector<vector<int>> &costs) {
10 // write your code here'
11 if(costs.size() == 0) return 0;
12 dp.resize(costs.size(), vector<int>(3,inf));
13 for(int i = 0; i < costs.size(); ++i){
14 for(int j = 0; j < 3; ++j){
15 if(i == 0){
16 dp[i][j] = costs[i][j];
17 } else {
18 vector<int> tmp = color(j);
19 dp[i][j] = min(dp[i-1][tmp[0]], dp[i-1][tmp[1]]) + costs[i][j];
20 }
21 }
22 }
23 return min(dp[costs.size() - 1][0], min(dp[costs.size() - 1][1], dp[costs.size() - 1][2]));
24 }
25 vector<int> color(int x){
26 vector<int> y;
27 if(x == 0){
28 y.push_back(1);
29 y.push_back(2);
30 return y;
31 } else if(x == 1){
32 y.push_back(0);
33 y.push_back(2);
34 return y;
35 } else {
36 y.push_back(1);
37 y.push_back(0);
38 return y;
39 }
40 }
41 };
