# 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.

Note:
All costs are positive integers.

Example:

``````Input: [[17,2,17],[16,16,5],[14,3,19]]
Output: 10
Explanation: Paint house 0 into blue, paint house 1 into green, paint house 2 into blue.
Minimum cost: 2 + 5 + 3 = 10.
``````

dp[i][j] = dp[i][j] + min(dp[i - 1][(j + 1) % 3], dp[i - 1][(j + 2) % 3])；

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

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

Github 同步地址：

https://github.com/grandyang/leetcode/issues/256

House Robber II

House Robber

Paint Fence

https://leetcode.com/problems/paint-house/

https://leetcode.com/problems/paint-house/discuss/68211/Simple-java-DP-solution

https://leetcode.com/problems/paint-house/discuss/68203/Share-my-very-simple-Java-solution-with-explanation.

https://leetcode.com/problems/paint-house/discuss/68252/Simple-15-line-code-with-O(n)-time-and-O(1)-memory-solution(Java)

LeetCode All in One 题目讲解汇总(持续更新中…)

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