INCREFF Software Developer Intern Interview Questions and Answers

Round duration - 70 Minutes
Round difficulty - Medium

Timing was 9:15AM. Platform was not very good. Questions were not well explained.

Q1. 
Merge Overlapping Intervals Problem Statement
Given a specified number of intervals, where each interval is represented by two integers denoting its boundaries, the task is to merge all overlapping interv...read more
Ans. Brute Force
1. We are given the function MERGEINTERVALS(), which takes a 2D vector representing the vector of intervals and returns another 2D vector which is the vector of merged intervals.
2. We create another function ISOVERLAP() to check if the current interval overlaps with the other interval.
3. Now we create an empty 2D vector “RES” to store finally merged intervals and another boolean vector “VIS” to mark if the current in...read more
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Q2. 
Rat in a Maze Problem Statement
You need to determine all possible paths for a rat starting at position (0, 0) in a square maze to reach its destination at (N-1, N-1). The maze is represented as an N*N ma...read more
Ans. Bactracking
Approach: We can start the traversal of the paths from the rat’s starting position, i.e. (0,0) keeping track of the visited cells during the traversal. We will recursively go through all the paths possible until the last index of the grid (destination) is reached, and add the path information using which the rat successfully reached the end.
 
Algorithm is as follows:
 
1. Take the starting position of th...read more
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Q3. 
Problem: Permutations of a String
Given a string STR consisting of lowercase English letters, your task is to return all permutations of the given string in lexicographically increasing order.
Explanatio...read more
Ans. Backtracking
The idea is to fix a character at a position and then find the permutations for rest of the characters.
Make a list ‘ans’ which will contain the permutations of the given string.
 
Algorithm:
Let’s define a function generatePermutaionsHelper(Str, l, r). This function generates the permutations of the substring which starts from index  ‘l’ and ends at index  ‘r’.
• Call the function: generatePermutai...read more
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Round duration - 90 minutes
Round difficulty - Medium

Timing was 10AM. The platform was quite good.

Q1. 
Maximum Size Rectangle Sub-Matrix with All 1's
Given an N x M binary matrix 'MAT', where N is the number of rows and M is the number of columns, determine the maximum area of a submatrix consisting entire...read more
Ans. 
If the height of bars of the histogram is given then the largest area of the histogram can be found. This way in each row, the largest area of bars of the histogram can be found. To get the largest rectangle full of 1’s, update the next row with the previous row and find the largest area under the histogram, i.e. consider each 1’s as filled squares and 0’s with an empty square and consider each row as the base.
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Q2. 
Maximum Sum Path in a Binary Tree
Your task is to determine the maximum possible sum of a simple path between any two nodes (possibly the same) in a given binary tree of 'N' nodes with integer values.
Ex...read more
Ans. 
For each node there can be four ways that the max path goes through the node:
1. Node only
2. Max path through Left Child + Node
3. Max path through Right Child + Node
4. Max path through Left Child + Node + Max path through Right Child
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Q3. 
Minimum Number of Swaps to Sort an Array
Find the minimum number of swaps required to sort a given array of distinct elements in ascending order.
Input:
T (number of test cases)
For each test case:
N (siz...read more
Ans. 
This can be easily done by visualizing the problem as a graph. We will have n nodes and an edge directed from node i to node j if the element at i’th index must be present at j’th index in the sorted array.
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Q4. 
Prefix to Infix Conversion
Transform a string representing a valid Prefix expression, which may contain operators '+', '-', '*', '/', and uppercase letters, into its corresponding Infix expression.
Examp...read more
Ans. 
Algorithm for Prefix to Infix:

Read the Prefix expression in reverse order (from right to left)
If the symbol is an operand, then push it onto the Stack
If the symbol is an operator, then pop two operands from the Stack
Create a string by concatenating the two operands and the operator between them.
string = (operand1 + operator + operand2)
And push the resultant string back to Stack
Repeat the above steps until end of Prefix
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Round duration - 70 minutes
Round difficulty - Medium

Timing was 9:15AM. Platform was not very good. Questions were not well explained.

Q1. 
Merge Overlapping Intervals Problem Statement
Given a specified number of intervals, where each interval is represented by two integers denoting its boundaries, the task is to merge all overlapping interv...read more
Add your answer
Q2. 
Rat in a Maze Problem Statement
You need to determine all possible paths for a rat starting at position (0, 0) in a square maze to reach its destination at (N-1, N-1). The maze is represented as an N*N ma...read more
Add your answer

Round duration - 90 minutes
Round difficulty - Medium

Timing was 10AM. The platform was user-friendly.

Q1. 
Maximum Size Rectangle Sub-matrix with All 1's Problem Statement
You are provided with an N * M sized binary matrix 'MAT' where 'N' denotes the number of rows and 'M' denotes the number of columns. Your t...read more
Add your answer
Q2. 
Binary Tree Maximum Path Sum Problem Statement
Determine the maximum path sum for any path in a given binary tree with 'N' nodes.
Note:
• A 'path' is defined as any sequence of adjacent nodes connected...read more
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Q3. 
Minimum Number of Swaps to Sort an Array
Find the minimum number of swaps required to sort a given array of distinct elements in ascending order.
Input:
T (number of test cases)
For each test case:
N (siz...read more
Add your answer
Q4. 
Prefix to Infix Conversion
Transform a string representing a valid Prefix expression, which may contain operators '+', '-', '*', '/', and uppercase letters, into its corresponding Infix expression.
Examp...read more
Add your answer