public class Solution {
private int quickSolve(int[] prices) {
int len = prices.length, profit = 0;
for (int i = 1; i < len; i++)
// as long as there is a price gap, we gain a profit.
if (prices[i] > prices[i - 1]) profit += prices[i] - prices[i - 1];
return profit;
}
public int maxProfit(int k, int[] prices) {
if (prices == null || prices.length < 1) return 0;
int len = prices.length;
if (k >= len / 2) return quickSolve(prices);
int[][] dp = new int[k + 1][len];
int res = 0;
for (int i = 1; i <= k; i++) {
int tempMax = dp[i - 1][0] - prices[0];
for (int j = 1; j < len; j++) {
dp[i][j] = Math.max(dp[i][j - 1], prices[j] + tempMax);
tempMax = Math.max(tempMax, dp[i - 1][j] - prices[j]);
res = Math.max(res, dp[i][j]);
}
}
return res;
}
}