Java Program : write a method to check if it is well formed expression. Eg: {[()]}

This question was asked in an interview that I found interesting.

Here you go.

I know, There are other ways to do it better.

                Map<Character, Character> exprssionMap = new HashMap<>();
exprssionMap.put('{', '}');
exprssionMap.put('[', ']');
exprssionMap.put('(', ')');

String inputExpression = "{[({{)}}]}";
int expressionLengh = inputExpression.length();
if (expressionLengh % 2 == 1) {
System.out.println("malformed Expression; Size of the Expression is not even                                           number");
} else {
for (int i = 0; i < expressionLengh / 2; i++) {
if (!exprssionMap.get(inputExpression.charAt(i))
.equals(inputExpression.charAt(expressionLengh - 1 - i))) {
System.out.println(
"Matching expression not found for: " +                                                                                                    inputExpression.charAt(i) + "; index:" + i);
}
}
}

Happy Coding.

Selenium Question

-          Assume, given web application is accessible in one Machine ( IP : 10.10.10.10)

-          You need to write selenium tests and run.

-          You are not allowed to install / download any software except browser in IP: 10.10.10.10.

How you do you achieve this?                                                 

Analysis:

-          We can start coding in our local laptop , later we can think about executing tests.

-          To find out locators ( xpaths / css / etc) , connect to the machine IP 10.10.10.10 via remote desktop and fetch as much info as needed.

Now Execution part,

-          When we execute our test in local, tests should run in the IP 10.10.10.10.

-          This can be achieved via selenium GRID.

-          Create a node in IP 10.10.10.10 and connect to a HUB ( either in your laptop / IP 10.10.10.10)

-          Write Remote web driver code instead of plain webdriver.

Just hit run. That’s all.

Logical Qn : Assume that you have 25 horses, and you want to pick the fastest 3 horses out of those 25. In each race, only 5 horses can run at the same time because there are only 5 tracks. What is the minimum number of races required to find the 3 fastest horses without using a stopwatch?

After analyzing a bit, Here are the pointers.
- We need to put all the horses into a race ( 5 at a time ) to find out the best 3 performers.
- Maximum 5 Horses in a race, so 5 times we need to conduct.
- After 5 Races, below is the table we can draw "ORDER by best performer"

Race1H1  -  Race2H6 -  Race3H11 -  Race4H16 -  Race5H21
Race1H2  -  Race2H7 -  Race3H12 -  Race4H17 -  Race5H22
Race1H3  -  Race2H8 -  Race3H13 -  Race4H18 -  Race5H23
Race1H4  -  Race2H9 -  Race3H14 -  Race4H19 -  Race5H24
Race1H5  -  Race2H10 -Race3H15 -  Race4H20 -  Race5H25

Our Aim is to find the best three performers. so, we can eliminate last two rows.
Reason: We are least bothered about 4th and 5th best in each race.
They can not be one among top three performers.

Our Target table is

Race1H1  -  Race2H6 -  Race3H11 -  Race4H16 -  Race5H21
Race1H2  -  Race2H7 -  Race3H12 -  Race4H17 -  Race5H22
Race1H3  -  Race2H8 -  Race3H13 -  Race4H18 -  Race5H23

Now Race # 6: all top players in each race:
i.e
Race1H1  -  Race2H6 -  Race3H11 -  Race4H16 -  Race5H21

Assume results are, 1st place Race1H1  ; 2nd place Race2H6 ; 3rd place Race3H11


Now Race # 7: will gives the 2nd and 3rd place horse.
i.e we need to conduct a race with below set.
                 -  Race2H6 -  Race3H11
Race1H2  -  Race2H7
Race1H3

why we eliminated other horses?

Elimination Set # 1
Race4H16 -  Race5H21
Race4H17 -  Race5H22
Race4H18 -  Race5H23

Reason: As 3rd best horse is Race3H11. so, above set is definitely is not in 1,2,3 positions.

Elimination Set # 2
Race3H12
Race3H13

Reason: same as above.

Elimination Set # 3
Race2H8

Reason: as Race1H1 is 1st , there may be chance for 2nd is Race1H2 or Race2H6
chance for 3rd is Race1H3, Race2H6, Race2H7, Race3H11
but not Race2H8

so, Answer is 7



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