American Express SDE-2 Interview Questions and Answers for Freshers

Round duration - 80 minutes
Round difficulty - Medium

Q1. 
Longest Increasing Path in Matrix Problem Statement
Given a 2-D matrix mat with 'N' rows and 'M' columns, where each element at position (i, j) is mat[i][j], determine the length of the longest increasing...read more
Ans. 
The problem involves finding the length of the longest increasing path in a 2-D matrix starting from a given cell.
• Use dynamic programming to keep track of the longest increasing path starting from each cell.

• Implement a recursive function to explore all possible paths from a cell.

• Update the length of the longest path for each cell based on the maximum path length from its neighbors.

• Consider edge cases such as boundary c...read more
Answered by AI
Add your answer

Round duration - 50 minutes
Round difficulty - Hard

It was purely Data Structures and Maths.

Q1. 
Arithmetic Progression Queries Problem Statement
Given an integer array ARR of size N, perform the following operations:
- update(l, r, val): Add (val + i) to arr[l + i] for all 0 ≤ i ≤ r - l.
- rangeSu...read more
Ans. 
Implement update and rangeSum operations on an integer array based on given queries.
• Implement update(l, r, val) by adding (val + i) to arr[l + i] for all i in range (0, r - l).

• Implement rangeSum(l, r) to return the sum of elements in the array from index l to r.

• Handle queries using 1-based indexing.

• Ensure constraints are met for input values.

• Output the sum of arr[l..r] for each rangeSum operation.
Answered by AI
Add your answer

Round duration - 70 Minutes
Round difficulty - Easy

Round duration - 30 Minutes
Round difficulty - Easy

Q1. 
Pattern Matching Problem Statement
Given a pattern as a string and a set of words, determine if the pattern and the words list align in the same sequence.
Input:
T (number of test cases)
For each test ca...read more
Ans. 
The problem involves determining if a given pattern aligns with a list of words in the same sequence.
• Iterate through the pattern and words list simultaneously to check for matching sequences.

• Use a hashmap to store the mapping between characters in the pattern and words in the list.

• Compare the mappings to determine if the pattern and words align in the same sequence.
Answered by AI
Add your answer

DSA, Leetcode medium -2 problems

Q1. Easy Leetcode Problem: Count of substrings with no repeating characters
Ans. 
Count substrings with unique characters in a given string
• Use a sliding window approach to keep track of unique characters in a substring

• Use a set to store characters in the current window and update the window accordingly

• Increment the count of valid substrings whenever a new character is added to the set
Answered by AI
Add your answer
Q2. Debugging a Java Code
Ans. 
Debugging a Java code involves identifying and fixing errors in the code to ensure it runs correctly.
• Start by understanding the error message or symptoms of the issue.

• Use debugging tools like breakpoints, watches, and logging to track the flow of the code.

• Review the code logic and check for common mistakes like typos, incorrect variable assignments, or logic errors.

• Test different scenarios to reproduce the issue and na...read more
Answered by AI
Add your answer

Q1. Design Parking System
Ans. 
Design a parking system with different types of parking spots
• Create classes for different types of parking spots (e.g. compact, regular, handicap)

• Implement methods for checking availability, reserving, and releasing spots

• Consider implementing a parking lot class to manage all parking spots
Answered by AI
Add your answer

Round duration - 45 Minutes
Round difficulty - Hard

Q1. 
Find the Duplicate Number Problem Statement
Given an integer array 'ARR' of size 'N' containing numbers from 0 to (N - 2). Each number appears at least once, and there is one number that appears twice. Yo...read more
Ans. 
Find the duplicate number in an integer array containing numbers from 0 to (N - 2).
• Iterate through the array and keep track of the frequency of each number using a hashmap.

• Return the number that appears twice in the array.

• The duplicate number is always present in the given array.
Answered by AI
Add your answer

Round duration - 50 Minutes
Round difficulty - Easy

Q1. 
Bubble Sort Problem Statement
Sort an unsorted array of non-negative integers using the Bubble Sort algorithm, which swaps adjacent elements if they are not in the correct order to sort the array in non-d...read more
Ans. 
Bubble Sort is used to sort an array of non-negative integers in non-decreasing order by swapping adjacent elements if they are not in the correct order.
• Iterate through the array and compare adjacent elements, swapping them if they are in the wrong order.

• Repeat this process until the array is sorted in non-decreasing order.

• Time complexity of Bubble Sort is O(n^2) in worst case.

• Example: For input [6, 2, 8, 4, 10], the o
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Medium

Q1. 
Unweighted Graph Shortest Path Problem
You are tasked with finding the shortest path between two houses in the city of Ninjaland, represented as an unweighted graph. The city has N houses numbered from 1 ...read more
Ans. 
Find the shortest path between two houses in a city represented as an unweighted graph.
• Use breadth-first search (BFS) algorithm to find the shortest path in an unweighted graph.

• Start BFS from the source house and keep track of the shortest path to each house.

• Once the destination house is reached, backtrack to find the shortest path.

• Consider using a queue data structure to implement BFS efficiently.
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Easy