JPMorgan Chase & Co. Machine Learning Engineer Interview Questions, Process, and Tips

Round duration - 60 Minutes
Round difficulty - Hard

Timings: Early morning 7am (60 mins )
Subsection 1 (30 mins): MCQ round having 30 questions of 11th and 12th Math (complex numbers, trigonometry, calculas), Probability (Expectancy, bayes theorem, other probability question), Coding (Input/Output Question, Time complexity, Stack Push and Pop, Prefix, Postfix).
Subsection 2 (30 mins): 2 Coding Question 1 easy level (Find max in array), other was medium level (Find all the elements in tree which are at same level, where level is depth of smallest path from root to leaf)

Questions were different for each candidate

Q1. 
Maximum Number by One Swap
You are provided with an array of N integers representing the digits of a number. You are allowed to perform an operation where you can swap the values at two different indices ...read more
Ans. Brute Force
The idea is to generate all the possible numbers by trying all the possible combinations of indices. We will run two nested loops to generate all numbers and inside the inner loop with we will have to compare the array, we get after swapping with the maximum number we get till this step.
1. Let’s say we have a given array ARR.
2. Let’s take an integer array of size N say MAX initialized to ARR, MAX[N] = ARR.
3. Iterate ...read more
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Q2. 
Find Paths in Binary Tree
Kevin has sketched a series of integers, forming a diagram that represents a binary tree. Challenged by a friend, Kevin needs to find all paths from the root to the leaf where th...read more
Ans. Depth First Search and Backtracking
The basic idea is to perform Depth First Search on the given binary Tree and keep track of the current sum and whenever reached the lead node check if the sum becomes equal to the ‘K’ then pick this path, otherwise just backtrack to the previous node and exclude the value of this leaf node from the current sum.
 
We are here using a helper function that is recursive in nature and i...read more
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Round duration - 30 minutes
Round difficulty - Medium

Interviewer greeted me and told this round is only on Probability.(This was scheduled same day at 3pm)
He asked Following Probability questions:
Q1: What is Random variable?
Q2: What is Sample space?
Q3: What is Conditional Probability? followed by a Numerical on it.
Q4: What is a Normal Distribution?
Q5: What is Bayes theorem? followed by a numerical on it.
Q6: probability of car accident in one hour is 1/4. What is the probability of accident in half hour?
Q7: Two die are thrown, what is the probability of getting multiple of 3. 
Q8: There is 10 Black socks in drawer, 10 white socks. What is the minimum number of socks we need to pick out such that we get a pair?

Round duration - 30 minutes
Round difficulty - Medium

Interviewer greeted me and told this round is only on Basic DSA.(This was scheduled same day at 3:30pm)
He asked Following questions:
Q1: Introduction and Explain your resume?
Q2: What if we have one class (which has array functionality) and other class (stack) which we will inherit from array class what could possibly go wrong here?
Q3: What is Static data member in Classes?
Q4: What is Static member function in Classes? Can static member functions call normal data member of classes?
Q5: you are given a 2D grid, each index has some value associated with it. From Bottom right cornor you need to find a path till Top left cornor where you can get maximum sum of values from index occuring on the path, You can go in Up direction, Left direction or diagonal up-left direction? 

I was asked for approach (No coding was done on compiler)

Q1. 
Paths in a Matrix Problem Statement
Given an 'M x N' matrix, print all the possible paths from the top-left corner to the bottom-right corner. You can only move either right (from (i,j) to (i,j+1)) or dow...read more
Ans. Recursion
The basic idea to solve this problem is to use recursion. Recursively call function   for next row ( row+1,col ) and next column ( row, col+1 ). If the row is equal to M-1 or the column is equal to N-1, then recursion is stopped.
 
Algorithm:
• Take an array or vector ‘path’, which will store the path we have to print.
• Start from the index (row, col) = (0,0).
• Add mat(row, col) to  ‘path.’
• Recursively ca...read more
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Round duration - 15 minutes
Round difficulty - Easy

This round happened around 5pm in evening, i got the call from the interviewer to join Zoom call immediately. In this round (it was kind of rapid fire round on DSA,)
Following questions were asked:
Q1: Introduce yourself and explain your resume.
Q2: What is your favorite data structure and why? I said it is Deque, as it is can be helpful in many questions
Q3: Explain what are segment trees. Also give a question were we can use them.
Q4: What are tries, and give one application of tries.
Q5: Given one array you need to give approach to find out all the permutation of the elements in it. (I gave recursive approach)
Q6: Given the same array and value k, you need to tell if sum of subset can be equal to k. (This question is modification of 0/1 Knapsack. I explained the recursive approach)

Interviewer told me to wait for last HR round (I was on cloud 9 after listening to this as it was elimination round)

Q1. 
Find Permutation Problem Statement
Given an integer N, determine an array of size 2 * N that satisfies the following conditions:
1. Each number from 1 to N appears exactly twice in the array.
2. The distanc...read more
Ans. Brute Force
The idea is to make an array with exactly two occurrences of each element from 1 to N. Then we will generate all possible permutations of this array and check if any permutation is valid or not.
The steps are as follows:
1. Let’s define a recursive function as generatePermutations(arr, answer, N,  start, end), where arr is the array containing the permutation, answer is array that will store the final answer...read more
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Q2. 
Subset Sum Equal To K Problem Statement
Given an array/list of positive integers and an integer K, determine if there exists a subset whose sum equals K.
Provide true if such a subset exists, otherwise r...read more
Ans. Recursion
The idea is to generate all possible subsets and check if any of them sums up to ‘K’. This can be done through recursion.
 
Here is the algorithm:
 
subsetSumToK(N , K , ARR):
1. Initialize integer variable ‘ANS’ = ‘helper(ARR, N, K)’. Here ‘helper’ is the recursive function that returns true/false.
2. If ‘ANS’ is equal to 1 then:
   • Return true.
3. Else:
   • Return false.
 
helper(ARR, N, K):
1. Base case: If ‘N’ is less tha...read more
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Round duration - 20 Minutes
Round difficulty - Easy

This round happened around 6:30pm in evening, i got the call from the interviewer to join Zoom call immediately. It was HR+(Probability mix round).
He asked me following questions:
Q1: Introduce and explain your resume.
As i was unable to solve 2 probability question in Round 2. The interviewer immediately asked me 2 probability questions back to back.
Q2: What is bayes theorem and a numerical on it.
Q3: If there is a frog which can go one step forward with probability 3/4. and one step backward with 1/4. What is expectancy to reach 7 steps forward.

I was unable to solve the last probability ques. Was on right track almost in end of interview.
2/18 students were selected for intern JPMC(Quant Research @ 1.5Lakhs stipend)