动态规划——Best Time to Buy and Sell Stock IV

 1 class Solution{
 2     public static int maxProfit(int k,int[] prices) {
 3         int nlen = prices.length;
 4         if(nlen<=1)return 0;
 5         else if(k>nlen/2) {
 6             int res = 0;
 7             for(int i = 1;i<nlen;i++)
 8                 if(prices[i]>prices[i-1])res+=(prices[i]-prices[i-1]);
 9             return res;
10         }else {
11             int temp = 0;
12             int[][]dp = new int[k+1][nlen];
13             Arrays.fill(dp[0],0);
14             for(int i = 0;i<=k;i++)
15                 dp[i][0] = 0;
16             for(int kt = 1;kt<=k;kt++) {
17                 for(int i = 1;i<nlen;i++) {
18                     temp = 0;
19                     for(int j = 0;j<=i;j++)
20                         temp = temp>(dp[kt-1][j]+prices[i]-prices[j])?temp:(dp[kt-1][j]+prices[i]-prices[j]);
21                     dp[kt][i] = dp[kt][i-1]>temp?dp[kt][i-1]:temp;
22                 }
23             }
24             return dp[k][nlen-1];
25         }
26     }
27 }