Hike Software Developer Intern Interview Questions and Answers

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 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
Ans. 
Find the maximum area of a submatrix with all 1's in a binary matrix.
• Iterate over each cell in the matrix and calculate the maximum area of submatrix with that cell as the top-left corner.

• Use dynamic programming to keep track of the maximum width of 1's ending at each cell.

• Update the maximum area as you iterate through the matrix.

• Return the maximum area found.
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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
Ans. 
Find the maximum path sum in a binary tree with 'N' nodes.
• Traverse the binary tree to find all possible paths and calculate their sums.

• Keep track of the maximum sum encountered during traversal.

• Consider both left and right child nodes while calculating the path sum.

• Handle null nodes represented by '-1' in the input.

• Return the maximum path sum for each test case.
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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. 
The minimum number of swaps required to sort a given array of distinct elements in ascending order.
• Use graph theory to solve the problem by counting cycles in the permutation.

• The number of swaps needed is equal to the number of cycles in the permutation minus one.

• Consider using a hashmap to keep track of visited elements to optimize the solution.

• Example: For input array [4, 3, 2, 1], the minimum number of swaps require...read more
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Q4. 
Infix to Postfix Conversion
Convert a given infix expression, represented as a string EXP, into its equivalent postfix expression.
Explanation:
An infix expression is formatted as a op b where the opera...read more
Ans. 
Convert infix expression to postfix expression.
• Use a stack to keep track of operators and operands.

• Follow the rules of precedence for operators.

• Handle parentheses to ensure correct order of operations.
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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. 
Find the maximum area of a submatrix consisting entirely of 1's in a binary matrix.
• Iterate over each cell in the matrix and calculate the maximum area of a submatrix with that cell as the top-left corner.

• Use dynamic programming to keep track of the maximum width of 1's ending at each cell in the current row.

• Update the maximum area as you iterate through the matrix and consider each cell as the bottom-right corner of th...read more
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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. 
Find the maximum sum of a simple path between any two nodes in a binary tree.
• Use a recursive approach to traverse the binary tree and calculate the maximum sum path.

• Keep track of the maximum sum path found so far while traversing the tree.

• Consider negative values in the path sum calculation to handle cases where the path can skip nodes.

• Update the maximum sum path if a new path with a higher sum is found.
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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. 
The minimum number of swaps required to sort a given array of distinct elements in ascending order.
• Use a graph-based approach to find cycles in the array for swapping

• Count the number of swaps needed to sort the array

• Example: For [4, 3, 2, 1], 2 swaps are needed to sort it to [1, 2, 3, 4]
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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. 
Convert a valid Prefix expression to its corresponding Infix expression.
• Use a stack to store operands and operators while traversing the prefix expression from right to left.

• Pop operands from the stack and form the infix expression by placing them between corresponding operators.

• Handle the precedence of operators to ensure correct order of operations in the infix expression.
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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
Ans. 
Find the maximum area of a submatrix with all 1's in a binary matrix.
• Iterate over each cell in the matrix and calculate the maximum area of submatrix with that cell as the top-left corner.

• Use dynamic programming to keep track of the maximum width of 1's ending at each cell.

• Update the maximum area as you iterate through the matrix.

• Return the maximum area found.
Answered by AI
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
Ans. 
Find the maximum path sum in a binary tree with 'N' nodes.
• Traverse the binary tree to find the maximum path sum.

• Keep track of the maximum sum encountered so far.

• Consider all possible paths in the tree to find the maximum sum.

• Example: For input 1 2 3 4 -1 5 6 -1 -1 -1 -1 -1 -1, the maximum path sum is 16.
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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. 
Find the minimum number of swaps required to sort an array of distinct elements in ascending order.
• Use graph theory to solve the problem by considering each element as a node and edges representing the swaps needed to sort the array

• Implement a graph-based approach like cycle detection to find the minimum number of swaps required

• Consider using an efficient sorting algorithm like bubble sort or selection sort to minimize...read more
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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. 
Convert a valid Prefix expression to its corresponding Infix expression.
• Use a stack to store operands and operators while traversing the prefix expression from right to left.

• Pop operands from the stack and form the infix expression by placing them between corresponding operators.

• Handle the precedence of operators to ensure correct order of operations.

• Ensure to handle parentheses to maintain the correct evaluation order...read more
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Round duration - 60 Minutes
Round difficulty - Easy

Q1. 
Maximum Difference in Matrix
Given an n x n matrix mat[n][n] of integers, find the maximum value of mat[c][d] - mat[a][b] for all possible indices where c > a and d > b.
Input:
The first line cont...read more
Ans. 
Find the maximum difference between elements in a matrix with specific conditions.
• Iterate through all possible pairs of indices (a, b) and (c, d) where c > a and d > b.

• Calculate the difference between mat[c][d] and mat[a][b] for each pair.

• Keep track of the maximum difference found so far.

• Return the maximum difference as the final result.
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Round duration - 20 Minutes
Round difficulty - Easy