class Solution {

public:

/**

* @param costs: n x 3 cost matrix

* @return: An integer, the minimum cost to paint all houses

*/

int minCost(vector<vector<int>> &costs) {

// write your code here

if (costs.empty() || costs[0].empty()) return 0;

int m = costs.size();

int n = costs[0].size();

vector<vector<int>> dp(m, vector<int>(n, 0));

dp[0][0] = costs[0][0];

dp[0][1] = costs[0][1];

dp[0][2] = costs[0][2];

for (int i = 1; i < m; i++)

{

dp[i][0] = min(dp[i - 1][1], dp[i - 1][2]) + costs[i][0];

dp[i][1] = min(dp[i - 1][0], dp[i - 1][2]) + costs[i][1];

dp[i][2] = min(dp[i - 1][0], dp[i - 1][1]) + costs[i][2];

}

return min(min(dp[m - 1][0], dp[m - 1][1]), dp[m - 1][2]);

}

};