Paint House
自己的写法:
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 int length = costs.size(); vector<vector<int> > dp(length + 1,vector<int>(3)); for(int i = 0;i < 3;i++) dp[0][i] = 0; for(int i = 1;i <= length;i++){ dp[i][0] = min(dp[i-1][1] + costs[i-1][0],dp[i-1][2] + costs[i-1][0]); dp[i][1] = min(dp[i-1][0] + costs[i-1][1],dp[i-1][2] + costs[i-1][1]); dp[i][2] = min(dp[i-1][0] + costs[i-1][2],dp[i-1][1] + costs[i-1][2]); } int min_num = INT_MAX; for(int i = 0;i < 3;i++){ min_num = min(min_num,dp[length][i]); } return min_num; } };
更优的写法:
https://www.cnblogs.com/grandyang/p/5319384.html
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]); } };