链接: 买卖股票的最佳时机之k天

题目描述

算法描述

编程代码

class Solution {
    
    
public:
    int maxProfit(int k, vector<int>& prices) {
    
    
        int n = prices.size();
        
        k = min(k,n/2);
        vector<vector<int>> f(n,vector<int>(k+1,-0x3f3f3f));
        auto g = f;
        f[0][0] = -prices[0];
        g[0][0] = 0;
        for(int i = 1;i<n;i++)
        {
    
    
            for(int j = 0;j<=k;j++)
            {
    
    
                f[i][j] = max(f[i-1][j],g[i-1][j] - prices[i]);
                g[i][j] = g[i-1][j];
                if(j - 1 >= 0)
                {
    
    
                    g[i][j] = max(g[i][j],f[i-1][j-1]+prices[i]);
                }
            }
        }
        int ret = 0;
        for(int j = 0;j<=k;j++)
        {
    
    
            ret = max(ret,g[n-1][j]);
        }
        return ret;
    }
};