lintcode:Paint House

•  Description
•  Notes
•  Testcase
•  Judge

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 x3 cost matrix. For example, costs[0][0] is the cost of painting house 0with 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.

Have you met this question in a real interview? 

Yes

 Notice

All costs are positive integers.

Example

Given costs = [[14,2,11],[11,14,5],[14,3,10]] return 10

house 0 is blue, house 1 is green, house 2 is blue, 2 + 5 + 3 = 10

class Solution {
public:
    /**
     * @param costs n x 3 cost matrix
     * @return an integer, the minimum cost to paint all houses
     */
    int minCost(vector>& costs) {
        // Write your code here
        if (costs.size() == 0) //检查边界条件非常重要
            return 0;
        
        int n = costs.size();
        
        vector> dp(n, vector(3));
        
        //dp[i][j] 表示计算到第i户时，他选择第j种颜色图墙时的最小价钱
        
        for (int i=0; i<3; i++)
        {
            dp[0][i] = costs[0][i];
        }
        
        
        for (int i=1; i