Say you have an array for which the ith element is the price of a given stock on day i.
Design an algorithm to find the maximum profit. You may complete at most k transactions.
public class Solution {
public int maxProfit(int k, int[] prices) {
if (prices == null || prices.length == 0) {
return 0;
}
if (k > prices.length) {
int res = 0;
for (int i = 0; i < prices.length-1; i++) {
int tmp = prices[i + 1] - prices[i];
if (tmp > 0) {
res += tmp;
}
}
return res;
}
int[][] global = new int[prices.length][k+1];
int[][] local = new int[prices.length][k+1];
for (int i = 0; i < prices.length-1; i++) {
int tmp = prices[i + 1] - prices[i];
for (int j = 0; j < k; j++) {
local[i+1][j+1] = Math.max(global[i][j]+Math.max(tmp,0), local[i][j+1] + tmp);
global[i+1][j+1] = Math.max(global[i][j+1], local[i+1][j+1]);
}
}
return global[prices.length-1][k];
}
}