Technical Rounds

Round 1:

• Determine if a given strict binary tree is balanced.
  • Criteria: Has equal nodes on both sides of the root node, and the depth from the root node is the same from both sides.
• Swap two variables without using a third variable.
• Find the frequency of each word from a given file using Java.

Round 2:

• Traverse a tree and print in spiral order.
• A matchstick puzzle: Four matchsticks are used to form a glass with an object inside. You can move at most two sticks, keeping the shape the same, to get the object out of the glass.
• Equals and Hashcode contracts.

Round 3:

• Code a function that returns a date string after adding a specified number of days. The input is a date string and the number of days as an integer.

Asked by HR

Puzzles:

• Three items are worth Rs. 5, Rs. 1, and 20 paise. You have Rs. 100 and need to purchase 100 items, using each item at least once.
• Using four sevens (7, 7, 7, 7) and any of the five operators (+, -, *, /, .) any number of times, make the value 100.
• Four people need to cross a bridge. At most two can cross at a time, and they have only one torch. Their crossing speeds are 1 second, 3 seconds, 5 seconds, and 7 seconds, respectively.

Technical Questions:

• Find the 5th highest-salaried person from the emp table using Oracle syntactical keywords. Nested queries are not allowed, and the complexity should be O(n).
• How will you map a many-to-many relationship into a relation table?

Find the 5th highest-salaried person from the emp table. Use Oracle syntactical keywords. You cannot use nested queries. Complexity should be O(n).