Best Time to Buy and Sell Stock IV

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];
    }
}