Best Time to Buy and Sell Stock III

public class Solution {
    public int maxProfit(int[] prices) {
        if(prices == null || prices.length <= 1)    return 0;
        int size = prices.length;
        int[] left = new int[size];  
        int[] right = new int[size];
        int min = prices[0];
        int max = prices[size-1];
        int rst = 0;
        for(int i=1; i<size; i++)
        {
            min = Math.min(min,prices[i]);
            left[i] = Math.max(left[i-1],prices[i]-min);
        }
        for(int j=size-2; j>=0; j--)
        {
            max = Math.max(max,prices[j]);
            right[j] = Math.max(right[j+1],max-prices[j]);
        }
        for(int k=0; k<size; k++)
        {
            rst = Math.max(rst, left[k]+right[k]);
        }
        return rst;
    }
}