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Software Engineer

ConsultAdd Inc

1 rounds | 2 Coding problems

Vivek Burada

Experienced | Mar 2025

Rejected

Interview preparation journey

Journey

I prepared for this company by reviewing previous interview experiences shared online and practicing coding problems on platforms like LeetCode and GeeksforGeeks.

Preparation

Topics: DSA, Javascript, OS

Application process

Where: Coding Ninjas Placement Cell

Eligibility: B.Tech CS/IT (Grad Year-2025 & 2024)

Interview rounds

Round

Medium

Online Coding Interview

Duration

Interview date7 Mar 2025

Coding problem2

1. Count Total Car Collisions on a Road

You are given a 0-indexed string directions of length n. Each character in directions[i] can be:

'L' — car moving left
'R' — car moving right
'S' — car staying at its current point

All moving cars travel at the same speed. Collisions are counted as follows:

When two cars moving in opposite directions collide, the number of collisions increases by 2.
When a moving car collides with a stationary car, the number of collisions increases by 1.

After a collision, the cars involved stop at the collision point and cannot move further. Cars cannot change their direction or state otherwise.

Task: Return the total number of collisions that will occur on the road.

Problem approach

Step 1: Read the input string.

Step 2: Initialize variables. For example collisions: to keep track of the total number of collisions. moveRight: to count consecutive R cars moving right. stationaryFound: a boolean flag to check if any stationary car (S) is encountered.

Step 3: Iterate through each car direction. Used a for loop to iterate through the directions string.

Step 4: Handle R cars (moving right). If the car is R, increment moveRight to track right-moving cars.

Step 5: Handle L cars (moving left). If a L car is found: If there were previous R cars, they collide. Add moveRight + 1 collisions (current L + all previous R cars). Reset moveRight to 0. If a stationary car was previously found, add 1 collision (L hits S).

Step 6: Handle S cars (stationary). Add all previous R cars as collisions. Reset moveRight to 0. Set stationaryFound to true to track future L cars colliding with S.

Step 7: Print the result.Display the total number of collisions using System.out.print(collisions).

2. Longest Wiggle Subsequence

A wiggle sequence is a sequence of numbers where the differences between successive numbers strictly alternate between positive and negative. The first difference (if it exists) may be either positive or negative.

A sequence with one element or two non-equal elements is trivially a wiggle sequence.

Examples:

[1, 7, 4, 9, 2, 5] is a wiggle sequence because the differences (6, -3, 5, -7, 3) alternate between positive and negative.
[1, 4, 7, 2, 5] is not a wiggle sequence because its first two differences are both positive.
[1, 7, 4, 5, 5] is not a wiggle sequence because it has a difference of zero.

Task: Given an integer array, determine the length of the longest wiggle subsequence.

Problem approach

Step 1: Import necessary libraries: java.util.*.

Step 2: Define the wiggleMaxLength function to calculate the longest wiggle subsequence.

Step 3: Handle edge cases: return the size if the list has fewer than 2 elements.

Step 4: Initialize variables: prevDiff = 0 and count = 1.

Step 5: Iterate through the list, calculating the difference between consecutive numbers.

Step 6: Check for alternating signs: If positive follows negative or vice versa, increment count. Update prevDiff with the current difference.

Step 7: Return the final count of the longest wiggle subsequence.