An application under home interview server sh fails to start and we need to find the cause of failure and resolve it so server can start successfully. The error we get is that the port 8080 is already in use. Something is occupying this port that doesn't let our server to start and to find what causes that we can use LSOF and then number of the port. We see that Python server is occupying the port and it has process ID of 15. We can kill this process, pseudo kill, and then the process id. Verify if something is running and we see that now nothing is running under the port. This time we got no error.

We have a deployment backend in the dev namespace and it's failing to start. Pods are stuck in image pull back off. Our task is to fix deployment so it successfully pull the image and enter the running state. Describe this to see details. When we look at events at the bottom, we can see that we get 401 unauthorized. The version is not the same as we have in image information. So we will need to fix this. We can do kubectl edit, name of the namespace dev, deploy, and then the name of the deployment backend, which will open to us vim editor. Second thing we need to do is we need to create a secret and we'll use command kubectl create. The secret type will be Docker Secret because it's a secret for the registry. Next, edit again our deployment. Find line that says spec and add image pull secrets configuration. And now our pod is running.

This question talks about storage classes and persistent volume claim expansion, meaning that if we have certain persistent volume claim with one gigabyte of storage, we can expand it to two gigabytes and further. First edit our storage class yaml. The main thing is allow volume expansion is being changed from false to true. Next we'll edit our persistent volume claim. We'll use Fast SC the one we've just created and the storage initially is going to be one gigabytes. We've been asked to create a pod. Cube CTL Run, which will create and run the pod, the name of the pod, the image and namespace, dry run client. The O YAML will output everything in YAML format. We can edit this file and add missing things like volume mounts and so on. There's one last thing to do in this question is to expand our pod. Type kubectl edit persistent volume claim. And what we will do here is we'll change storage from one to two.

We have a Node.js project where the CI workflow downloads all the dependencies from scratch on each and every run. That is very slow and wasteful because the dependencies rarely change between the runs. We need to add caching so that the dependencies are downloaded once and reused on each and every ...

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def letter_combinations(digits: str) -> list[str]:
if not digits:
return []

digit_to_char = {
    "2": "abc", "3": "def", "4": "ghi", "5": "jkl",
    "6": "mno", "7": "pqrs", "8": "tuv", "9": "wxyz"
}

res = []

def dfs(i, current_string):
    if i == len(digits):
        res.append(current_string)
        return
        
    for char in digit_to_char[digits[i]]:
        dfs(i + 1, current_string + char)
        
dfs(0, "")
return res

We have a customers table with columns like city, customer ID, first name, last name, postal code, state, and street address. Our job is to combine them into one single column called full address. Some columns could have null values, meaning some customers might be missing a city, state, or postal code. In this case, they should be excluded from the full address. One more possible case is that all components are missing. In this case, we should return an empty string. For this problem, we will need to use COALESCE function. COALESCE function takes a list of values and returns the first one that is not null. For this reason, we need to know the case statement. The idea is basically like an if else statement in any programming language. We will use the concatenation sign in order to connect them one by one. The last thing we have to do is sorting everything out in ascending order, which can be done using order by.

Build an end-to-end ETL pipeline using pandas to clean messy e-commerce data, standardize formats, calculate derived fields, and export results using method chaining and pipe functions.

Definition for a binary tree node.

class TreeNode:

def init(self, val=0, left=None, right=None):

self.val = val

self.left = left

self.right = right

def kth_smallest(root: Optional[TreeNode], k: int) -> int:
stack = []
curr = root

while curr or stack:
    while curr:
        stack.append(curr)
        curr = curr.left
        
    curr = stack.pop()
    k -= 1
    
    if k == 0:
        return curr.val
        
    curr = curr.right
    
return -1

Definition for a binary tree node.

class TreeNode:

def init(self, val=0, left=None, right=None):

self.val = val

self.left = left

self.right = right

def max_path_sum(root: Optional[TreeNode]) -> int:
res = -float('inf')

def get_max_gain(node):
    nonlocal res
    if not node:
        return 0
        
    left_gain = max(get_max_gain(node.left), 0)
    right_gain = max(get_max_gain(node.right), 0)
    
    current_max_path = node.val + left_gain + right_gain
    res = max(res, current_max_path)
    
    return node.val + max(left_gain, right_gain)
    
get_max_gain(root)
return int(res)

Objective

The objective of this SQL interview question is to write a query that calculates the average payment delay for invoices that have been paid. The payment delay is specifically defined as the difference in days between the payment_date and the issue_date of each invoice. It's crucia...

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Objective

Write an SQL query to calculate the percentage of orders that have been returned for each product. The result should include the product name and the return percentage. The return percentage should be rounded to two decimal places. The results should be ordered by the return percentag...

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How to Calculate Cost Per Acquisition for Each Marketing Channel

In this SQL interview question, the objective is to determine the cost per acquisition for each marketing channel based on two tables, marketing_expenses and sales.

Objective Overview

You will need to calculate the cost...

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