# DE-Shaw & Co Interview Experience | On-Campus Internship

Last Updated :
18 Sep, 2019

De- Shaw & Co visited our campus for hiring Interns for Summer 2020.

**Round 1: (Online Coding Round – 75 min on Hackerrank)**

Question 1 : Price of share increase by 1 for first 3 days. Decrease by 2 for next 3 days. Increase by 3 for next 3 days and so on. Given a price of share at start and number of days N . Find the price of share after N days.

Question 2 : Given a number N, find the lexicographical rth smallest permutation of numbers from [1, N]. Output the last number of permutation.

5 students were selected for next round from 90 students.

**Round 2: (Technical Round 1 – 50 min)**

Question 1 : Given a Pre – Order and In – Order Traversal, find the binary tree

Question 2 : Given a large library of books, and a set of words. Find the book which has all the words present in set. (we can use hash-map)

Question 3 : Given stocks values at N days, find the maximum profit we can gain by selling and purchasing stocks on different days. (For each day, just find the maximum sell value of stock present in days following that day)

Question 4 : What is encapsulation, inheretance, Virtual Function .

Question 5Â : How Virtual Functions work ( Vtable and Vptr). Draw Vtable and Vptr for given set of classes.

Question 6 : Why object is passed as reference in copy constructor and not by value or pointer.

**Round 3: (Technical Round 2 – 50 min)**

Question 1 : Given n roads on one side of river and m roads on other side of river. We wish to connect same width road across the rivers but without any intersection of roads . Find the maximum number of roads we can built.

Question 2 : Given a binary tree, we need to place minimum number of cameras on node, such that all nodes in binary tree are under surveillance . if we place a camera on a node, it can cover its both children, itself and its parent.Â ( Use bottom up approach to find minimum number of cameras).

Unfortunately, I was not selected for HR Round.

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