Qualcomm interview experience Real time questions & tips from candidates to crack your interview
Associate Engineer
Qualcomm
3 rounds | 7 Coding
problems
Selected Interview preparation journey
Journey
During my B Tech, I started practicing coding questions and participating in interview mocks. Till then, I solved many questions in all the practicing websites.
Application story
I applied through a referral and then called me for an interview. The interview went on smoothly and i got selected.
Why selected/rejected for the role?
I was selected because I have strong aptitude and coding practices. I was selected because I was able to give good, optimized approaches. I learn from this selection that practice mock interviews.
Preparation
Duration: 3 months
Topics: Data Structures, Algorithms, Dynamic Programming, OOPS, OS, DBMS, CN
Tip 1 : Focus on DSA-practice.
Tip 2 : Prepare CS fundamentals.
Tip 3 : Do at least two development projects.
Application process
Where: Referral
Eligibility: No
Tip 1 : Try to follow a basic format and highlight important achievements.
Tip 2 : Mention at least two good projects.
Interview rounds
01
Round
Medium
Video Call
Duration60 mins
Interview date19 Jun 2021
Coding problem2
1. Maximum Subarray Sum
Moderate
35m average time
81% success
0/80
Asked in companies
You are given an array 'arr' of length 'n', consisting of integers.
A subarray is a contiguous segment of an array. In other words, a subarray can be formed by removing 0 or more integers from the beginning and 0 or more integers from the end of an array.
Find the sum of the subarray (including empty subarray) having maximum sum among all subarrays.
The sum of an empty subarray is 0.
Example :
Input: 'arr' = [1, 2, 7, -4, 3, 2, -10, 9, 1]
Output: 11
Explanation: The subarray yielding the maximum sum is [1, 2, 7, -4, 3, 2].
Problem approach
To solve this, I applied Kadane's algorithm, where you keep two variables: one stores the maximum sum of the contiguous subarray ending at the current index, and the other stores the maximum sum of the contiguous subarray found so far.
2. Trapping Rain Water
Moderate
15m average time
80% success
0/80
Asked in companies
You have been given a long type array/list 'arr’ of size 'n’.
It represents an elevation map wherein 'arr[i]’ denotes the elevation of the 'ith' bar.
Print the total amount of rainwater that can be trapped in these elevations.
Note :
The width of each bar is the same and is equal to 1.
Example:
Input: ‘n’ = 6, ‘arr’ = [3, 0, 0, 2, 0, 4].
Output: 10
Explanation: Refer to the image for better comprehension:
Note :
You don't need to print anything. It has already been taken care of. Just implement the given function.
Problem approach
Iterate over every elevation or element and find the maximum elevation to the left and right of it. For example, the maximum elevation to the left of the current elevation or element that we are examining is ‘maxLeftHeight,’ and the maximum elevation to the right of it is ‘maxRightHeight.’ Take the minimum of ‘maxLeftHeight’ and ‘maxRightHeight’ and subtract it from the current elevation or element. This will be the amount of water that can be stored at this elevation. Compute the amount of water that each elevation can store and sum them up to return the total units of water that can be stored.
02
Round
Medium
Video Call
Duration60 mins
Interview date24 Jun 2021
Coding problem2
1. LCA of three nodes
Easy
20m average time
60% success
0/40
Asked in companies
You have been given a Binary Tree of 'N' nodes where the nodes have integer values and three integers 'N1', 'N2', and 'N3'. Find the LCA(Lowest Common Ancestor) of the three nodes represented by the given three('N1', 'N2', 'N3') integer values in the Binary Tree.
For example:
For the given binary tree: the LCA of (7,8,10) is 1
Note:
All of the node values of the binary tree will be unique.
N1, N2, and N3 will always exist in the binary tree.
Problem approach
It was a standard question, so, it was easy to solve.
2. Set Matrix Zeros
Easy
30m average time
65% success
0/40
Asked in companies
You are given an N x M integer matrix. Your task is to modify this matrix in place so that if any cell contains the value 0, then all cells in the same row and column as that cell should also be set to 0.
Requirements:
- If a cell in the matrix has the value 0, set all other cells in that cell's row and column to 0.
- You should perform this modification in place (without using additional matrices).
You must do it in place.
For Example:
If the given grid is this:
[7, 19, 3]
[4, 21, 0]
Then the modified grid will be:
[7, 19, 0]
[0, 0, 0]
Problem approach
In this first approach, I suggested storing which columns and rows have zeroes in a separate matrix and then running a loop again to make rows and columns containing zeroes into zeroes. The interviewer asked me to optimize this by reducing the space complexity. So, the approach I proposed was to store a zero at the 0th index of every column and row if any zeroes exist in that column or row.
03
Round
Easy
Video Call
Duration60 mins
Interview date27 Jun 2021
Coding problem3
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