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.
Companies:
LinkedIn
Related Topics:
Dynamic Programming
Similar Questions:
// OJ: https://leetcode.com/problems/paint-house/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(1)
class Solution {
public:
int minCost(vector<vector<int>>& costs) {
if (costs.empty()) return 0;
for (int i = 1; i < costs.size(); ++i) {
for (int j = 0; j < 3; ++j) costs[i][j] += min(costs[i - 1][(j + 1) % 3], costs[i - 1][(j + 2) % 3]);
}
return *min_element(costs.back().begin(), costs.back().end());
}
};