# Algorithm Interview Questions

interview questions shared by candidates

## Algorithm Interview Questions

Consider an X x Y array of 1's and 0s. The X axis represents "influences" meaning that X influences Y. So, for example, if $array[3,7] is 1 that means that 3 influences 7. An "influencer" is someone who influences every other person, but is not influenced by any other member. Given such an array, write a function to determine whether or not an "influencer" exists in the array. |

I have a log that consists of more than 100 million lines. Each line is just a data about user login, login time, etc. I want to sort them based on user login, and then if there is a tie based on login time, etc. However, I have limited memory, so don't think of storing all of them in an array. The memory can only hold n data where n is much smaller than 100 millions. You can access the disk though although it is much slower. How will you do it so that it is as efficient as possible? |

Given an array of integers, all but one of which appears an even number of times, find the one integer which appears an odd number of times. Upon completion, asked to improve the algorithm in terms of both time and space, eventually asked to do it in O(n) time and constant space. |

Given a string of format '2+3*2-1', calculate and return the result. No parenthesis in the input, just integers and + - * / operators. Operator precedence has to be considered. Linear time complexity and minimal data structure use is preferred. |

Write a function that finds the square root of a decimal number. |

How would you write a sort routine to ensure that identical elements in the input are maximally spread in the output? |

I was asked two questions. Q 1. You are given two version numbers of a software, like Version 10.3.4 and Version 10.3.41. Write a program to find out which of the version numbers are the latest. If version 1 is latest output -1, if version number 2 is latest output +1 else output 0 if same version. Both the version numbers are taken as string. He also asks to make the program of minimum time complexity as we can. At the end he also asked the difference between an iterative program and one with recurrence and their advantages and disadvantages. Q 2. Given two files with a list of application IDs (or some kind of data) stored in them , write a program to compare the data in the two files and output all the common data found in each. What data structure would you use and why ? Give a minimum time and space complexity algorithm. Why did you choose the particular data Structure or algorithm ? |

fair, lot of position related tech questions. Given a string "Keyword" find whether the characters exist in a String "Target" in the same order but not necessarily next to each other Keyword cat aaa Target cbate abcde Output YES NO |

How do you reverse a linked list |

In a BST write a program to find 2 nodes x and y such that X+y=k |

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