SDE - 1

Given a string 'S' of length 'N' and a character 'C', the task is to count the occurrence of the given character in the string.

Return the total number of times the character 'C' appears in the string 'S'.

For Example :

Let 'N' = 5, 'S' = "bbacb", 'C' = 'b'.
The character 'b' appears 3 times in the string "bbacb".
Therefore, the answer is 3.

There is a country with 'N' cities and 'M' bidirectional roads of 3 types.

Type 1: Two Wheeler Road, It means only vehicles having two wheels can use this road.
Type 2: Four Wheeler Road, It means only vehicles having four wheels can use this road.
Type 3: Both two and four Wheeler Road, It means this road can be used by both type of vehicles.

The problem is to find the maximum number of roads that can be removed such that a path exists for every pair of cities for each two-wheeler and four-wheeler vehicle.

Note:

1. Roads may form a cycle.

2. The cities do not have multiple same roads i.e all the roads are unique.

3. If every city cannot be reached, then return -1.

• Explain indexing in databases.
• What are the types of indexing, and why is it used?

You are given a string 'S'. Your task is to check whether the string is palindrome or not. For checking palindrome, consider alphabets and numbers only and ignore the symbols and whitespaces.

Note :

String 'S' is NOT case sensitive.

Example :

Let S = “c1 O$d@eeD o1c”.
If we ignore the special characters, whitespaces and convert all uppercase letters to lowercase, we get S = “c1odeedo1c”, which is a palindrome. Hence, the given string is also a palindrome.

Given a sequence of numbers ‘ARR’. Your task is to return a sorted sequence of ‘ARR’ in non-descending order with help of the merge sort algorithm.

Example :

Merge Sort Algorithm -

Merge sort is a Divide and Conquer based Algorithm. It divides the input array into two-parts, until the size of the input array is not ‘1’. In the return part, it will merge two sorted arrays a return a whole merged sorted array.

The above illustrates shows how merge sort works.

Note :

It is compulsory to use the ‘Merge Sort’ algorithm.

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• What is the difference between an abstract class and an interface? (Learn)
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