SDE - 1

You are given an array ‘ARR’ of size ‘N’ containing each number between 1 and ‘N’ - 1 at least once. There is a single integer value that is present in the array twice. Your task is to find the duplicate integer value present in the array.

For example:

Consider ARR = [1, 2, 3, 4, 4], the duplicate integer value present in the array is 4. Hence, the answer is 4 in this case.

Note :

A duplicate number is always present in the given array.

Ninja is given a binary string ‘S’ of size ‘N’ by his friend, the task is to check if the binary string ‘S’ can be sorted in decreasing order by removing any number of the non-adjacent characters. Since Ninja is busy with some work he is asking for your help. Can you help him?

Note:

A binary string is a string in which all characters are either ‘1’ or ‘0’.

The order is not strictly decreasing.

You pull out 2 balls, one after another, from a bag which has 20 blue and 13 red balls in total. If the balls are of similar colour, then the balls are replaced with a blue ball, however, if the balls are of different colours, then a red ball is used to replace them. Once the balls are taken out of the bag, they are not placed back in the bag, and thus the number of balls keep reducing. Determine the colour of last ball left in the bag.