## Google Interview Question

Software Engineers**Country:**United States

I could only do it in O(n^2). I am sure we can do it in O(n).

```
import java.util.Map;
import java.util.HashMap;
public class StockMaximumProfit {
public static void main(String[] args) {
int prices[] = new int[] {2, 30, 15, 10, 8, 25, 80};
Map<Integer, Integer> bestBuySellCombination = new
HashMap<Integer, Integer> ();
int maximumPriceDifference = 0;
int temporaryPriceDifference = 0;
int min = 0;
for (int i=0; i<prices.length; i++) {
for (int j=i+1; j<prices.length; j++) {
if (prices[j] > prices[i]) {
if (prices[j] >= min) {
min = prices[j];
temporaryPriceDifference = prices[j] - prices[i];
if (temporaryPriceDifference >
maximumPriceDifference) {
maximumPriceDifference =
temporaryPriceDifference;
bestBuySellCombination.
put(prices[i],prices[j]);
}
} else {
min = 0;
break;
}
} else {
break;
}
}
}
for (Map.Entry<Integer, Integer> itr : bestBuySellCombination.entrySet()) {
System.out.println("Best combinations are: " + itr.getKey() + " and " + itr.getValue());
System.out.println("The difference being: " + (itr.getValue() - itr.getKey()));
}
}
}
```

- deep March 10, 2017