# Easy to understand solution in java with explaination for beginners.

• ``````public class Solution {
//Compute the max profit we can get start from day 0  to day " i " with no more than one transaction(one buy and one sell), save the result in int[] front;
public static void computeFront(int[] prices, int[] front)
{
int bought = prices[0];
int max = 0;
for(int i = 0; i < prices.length;i++)
{
if(prices[i] > bought)
{
max = Math.max(max,prices[i] - bought);
}
else
bought = prices[i];
front[i] = max;
}
}
//Compute the max profit we can get start from day " i " to the end with no more than one transaction(one buy and one sell) ,save the result in int[] back;
public static void computeBack(int[] prices, int[] back)
{
int sell = prices[prices.length - 1];
int max = 0;

for(int i = prices.length - 2; i >= 0;i--)
{
if(prices[i] < sell)
{
max = Math.max(max, sell - prices[i]);
}
else
sell = prices[i];
back[i] = max;
}
}
public static int maxProfit(int[] prices) {

if(prices == null || prices.length < 2)
return 0;
int len = prices.length;
int maxProfit = 0;
int[] front = new int[len];
int[] back = new int[len];
computeFront(prices,front);
computeBack(prices,back);
for(int i = 1 ; i < len ;i++)
{
//Split the whole process into two parts start from day 0, and find the largest combination of the two parts;
maxProfit = Math.max(maxProfit, front[i]+back[i]);
}

return maxProfit;

}
}``````

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