# Flipkart Interview Experience | Set 42 (On Campus for SDE 1)

• Difficulty Level : Hard
• Last Updated : 26 Apr, 2018

Round 1: Online Coding Round

There were 3 questions and 90 minutes.

1. Question was based on union find algorithm (all test cases passed only if union by rank and path compression was used). Refer this.

2. Check if a given array can represent Preorder Traversal of Binary Search Tree. Refer this.

3. A simple ad-hoc problem.

Round 2: Technical Interview Round

1. Given a string find the first non repeating char in first function call, second non repeating char in second func call and so on.

2. Convert an arbitrary Binary Tree to a tree that holds Children Sum Property. Refer this.

3. How to print maximum number of A’s using given four keys. Refer this.

Round 3: Technical Interview Round

1. Given the arrival and departure of n guests find the maximum number of guests at any point of time.
Similar to this.

2. Given an array, modify it such that a[i] contains product of a[0] to a[i-1] and a[i+1] to a[n-1]. Do it without using the division operator.Refer this.

3. Convert a sorted DLL to balanced BST in-place. Refer this.

Round 4: Hiring Manager Round

1. Asked about my internships
2. Asked about my projects in detail
3. Puzzle: Given a 3×3 matrix having numbers from 1 to 9 without repetition. Find 3 more configurations of the matrix such that numbers previously in the same row can be in the same row in only one of the three configurations.

Round 5: Technical Interview Round

1. Given n, print all n digit numbers such that the digits are in non-decreasing order. Refer this.

2. Given a N x M matrix of 1’s and 0’s find the maximum area rectangle that have all 1’s. Refer this.

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