lintcode 515. Paint House

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 + ,vector<int>());
        for(int i = ;i < ;i++)
            dp[][i] = ;
        for(int i = ;i <= length;i++){
            dp[i][] = min(dp[i-][] + costs[i-][],dp[i-][] + costs[i-][]);
            dp[i][] = min(dp[i-][] + costs[i-][],dp[i-][] + costs[i-][]);
            dp[i][] = min(dp[i-][] + costs[i-][],dp[i-][] + costs[i-][]);
        }
        int min_num = INT_MAX;
        for(int i = ;i < ;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[].empty()) return ;
        vector<vector<int>> dp = costs;
        for (int i = ; i < dp.size(); ++i) {
            dp[i][] += min(dp[i - ][], dp[i - ][]);
            dp[i][] += min(dp[i - ][], dp[i - ][]);
            dp[i][] += min(dp[i - ][], dp[i - ][]);
        }
        return min(min(dp.back()[], dp.back()[]), dp.back()[]);
    }
};