Analyst Trainee

Ninja wants to travel from his house to a given destination, which is ‘X’ miles from his house. Along the way, he needs to fill gas in his vehicle. He knows there are ‘Y’ stations in his way. He also knows the distance between the station and his house, and how many liters of gas that particular station has.

Ninja starts his journey, with an infinite capacity of the tank filled with ‘Z’ liters of starting fuel. Suppose his vehicle uses 1 liter of gas for every mile, and ninja can stop at any gas station, transfer all the available gas at that station and then move ahead.

Now, you need to find out what is the minimum number of stops Ninja must make to reach his desired destination.

Note:

Note that if Ninja reaches a particular stop with no fuel, it can still fill his tank at that stop and continue his journey ahead. Similarly, if he reaches his destination with no fuel, it is still considered to have arrived.

For example :

Given X = 10, Y = 4, ARR[Y] = {[1, 6], [2, 3], [3, 3], [6, 4]} and Z = 1
So the path followed in this case would look like this:

Ninja starts with 1L of gas. 
Drives to the first gas station at position 1, using 1L of gas, then refueling with 6L of gas.
Then, drive to position 6, using 5L of gas, then refueling 4L in the current 1L of gas, making it a total of 5L of gas.
Finally, drive to the destination consuming 4L of gas.
So, Ninja made 2 refueling stops before reaching the destination. So, you need to print 2. 

It’s black friday and the supermarket near Ninja’s house is offering a special discount to every Nth customer that generates a bill. You are initially given 2 arrays, “PRODUCTS” and “PRICES” where “PRODUCTS[i]” represents the ID of the ith product and “PRICES[i]” represents the price of the ith product per unit. You are also given an integer “DISCOUNT” which represents the discount percentage for every nth customer (i.e. the effective amount to be paid would be ‘(100 - discount) / (100 * amount’).

For each customer that visits the store, you are given 2 arrays, “PRODUCTID” and “QUANTITY” where “PRODUCTID[i]” represents the ID of the ith product and “QUANTITY[i]” represents the quantity of the ith product purchased by the customer.

Your task is to implement the following 2 functions:

1. blackFriday(int N, int discount, int[] products, int[] prices) where every Nth customer receives a discount, “discount” is the discount percentage, “products” contains the product IDs, and “prices” contains the prices of products.

2. generateBill(int[] productID, int[] quantity) where “productID” contains the product IDs and “quantity” contains the quantities of products purchased by the customer.

Ninja has recently joined the FBI. Ninja got some secret information ‘SECRET_INFORMATION’ which he wants to share with his team. But he can not send this information directly because of the hackers and security threats they pose.

So Ninja decides to encode this ‘SECRET_INFORMATION’ and then send the encoded ‘SECRET_INFORMATION’ to his team members. This way, only his team members can decode this information and thus share it safely.

As Ninja is busy extracting the ‘SECRET_INFORMATION, he asks you for help.

Can you help Ninja and his friends with encoding and decoding the ‘SECRET_INFORMATION’?

Note:

1. The ‘SECRET_INFORMATION’ may contain any possible character out of 256 valid ASCII characters.
2. While decoding the ‘SECRET_INFORMATION’ do not use class members / global/static variables.
3. Do not use any inbuilt library method/function for decoding the ‘SECRET_INFORMATION’.

You are given a string 'STR'. The string contains [a-z] [A-Z] [0-9] [special characters]. You have to find the reverse of the string.

For example:

 If the given string is: STR = "abcde". You have to print the string "edcba".

follow up:

Try to solve the problem in O(1) space complexity.