SDE - 1

Step 1 : Looks like a greedy problem where you want to take the max values. Run some dry cases and see if some case violates it.
Step 2 : Try a brute force approach with 3 loops. Run three nested loops to iterate through all triplets. For every triplet, compute the required value and keep track of maximum and finally return the same.
Step 3 : Precompute values and stores them using extra space. The first key observation is i ≤ j ≤ k, so x*a[i] will always be the left maximum, and z*a[k] will always be the right maximum. Create a left array where we store the left maximums for every element. Create a right array where we store the right maximums for every element. Then for every element, calculate the maximum value of the function possible. For any index ind, the maximum at that position will always be (left[ind] + j * a[ind] + right[ind]), find the maximum of this value for every element in the array and that will be your answer.

Step 1 : Visualize the problem. Two circles can touch at 1 point minimum and in such a case the distance between centres is sum of radii. So if sum of radii > distance between centres, they do not touch.
Step 2 : Code the problem to determine distance between centres and compare it with R1 + R2

Tip 1 : Be clear about basic concepts, they shared some resource links, go through that properly
Tip 2 : Don't lie about any project. They start asking in depth as to why did you use a particular tech stack and why not the other. So you should know your project and choices inside out.
Tip 3 : Be thorough with SQL and noSQL if you mention it
Tip 4 : Be sure to know why you use a particular language. They might ask why don't you prefer Java over C++ or Python

Tip 1 : Try to be calm, stay firm in your point
Tip 2 : Accept criticism if required, don't be arrogant or headstrong
Tip 3 : Clearly explain why you have certain thoughts or expectations, it's better to go through the company website once to understand what they do