Sigmoid Software Developer Interview Questions and Answers

Q1. DSA Next Greater element 2 Cycle in Linked List and if cycle remove it Best time to buy and sell stocks Coin Change
Ans. 
Key DSA problems: Next Greater Element, Cycle in Linked List, Stock Trading, and Coin Change.
• Next Greater Element: Find the next greater number for each element in an array. Example: For [4, 5, 2, 10], result is [5, 10, 10, -1].

• Cycle in Linked List: Detect and remove a cycle using Floyd's Tortoise and Hare algorithm. If a cycle exists, find the start and remove it.

• Best Time to Buy and Sell Stocks: Maximize profit by fi...read more
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Q2. Pyspark Optimisation techniques Wide and Narrow Transportmations Application Master
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Q3. SQL Top 3 salaries per department Total working hours for an employee
Ans. 
Retrieve the top 3 salaries from each department and calculate total working hours for each employee using SQL queries.
• Use the ROW_NUMBER() function to rank salaries within each department: SELECT *, ROW_NUMBER() OVER (PARTITION BY department_id ORDER BY salary DESC) AS rank FROM employees.

• Filter the results to get only the top 3 salaries: WHERE rank <= 3.

• To calculate total working hours, use SUM() function: SELECT ...read more
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Q1. Valid parentheses
Ans. 
Valid parentheses check ensures every opening bracket has a corresponding closing bracket in the correct order.
• Use a stack to track opening parentheses. Example: '(()' -> push '(', push '(', pop ')' -> stack: ['(']

• For each closing parenthesis, check if the stack is not empty and matches the last opened. Example: '()' -> valid.

• An empty stack at the end indicates all parentheses were matched. Example: '(()())' -...read more
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Q2. Currying with arrow function
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Currying is a technique in functional programming where a function with multiple arguments is transformed into a sequence of nested functions, each taking a single argument.
• Currying can be achieved using arrow functions in JavaScript.

• Arrow functions automatically bind 'this' and do not have their own 'this' value.

• Example: const add = a => b => a + b;

• Example: const addFive = add(5); const result = addFive(3); // result ...read more
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Q1. DFS related problem
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Q2. Machine coding round
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3 questions 3 sum linked list missing sum

Q1. System Design and hr principles
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System design involves creating a high-level architecture of a software system, while HR principles focus on managing people effectively.
• System design involves identifying components, defining their interactions, and ensuring scalability and reliability.

• HR principles include hiring the right talent, providing training and development opportunities, and fostering a positive work culture.

• Both system design and HR princip...read more
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Q2. Projects discussion
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First round was aptitude with coding round it was easy

Q1. To check communication
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Q1. Ask question based on datastructures
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