C code. C code run. Run code run… please!
Question: http://codility.com/demo/take-sample-test/tape_equilibrium Question Name: TapeEquilibrium The variable of head stores the sum of the heading part of the tape. And the variable of tail stores the sum of tailing part. Then, we move the index from 2nd position to the … Read More »
Question: http://codility.com/demo/take-sample-test/perm_missing_elem Question Name: PermMissingElem or PermMissingElement The main challenge of this question is the XOR operations: X^X=0, and 0^X=X. Logically, the addition and subtraction operations also are able to do this work. But taking the overflow in computer into … Read More »
Question: https://codility.com/demo/take-sample-test/frog_jmp Question Name: FrogJmp This is a very easy question. If with C, one statement is enought. UPDATE on 2017/11/29: Codility changed Python from 2.X to 3.X. So the integer division needs to be updated to “//” from “/”. … Read More »
There are some public airfare watchdogs online. But we still have tons of reasons to set up a private one. For example, we do not want to share our email address, considering privacy and/or spam. Additionally, private watchdog has quicker … Read More »
Before solving this problem, we introduce a simple library of stack with integers. Many following questions need an integer stack. Not to reinvent the wheel in our following solutions, we make a standalone integer stack library. Actually, we should do … Read More »
The first part of this question is easy: use a set of stacks to mimic a single stack. In the second part, we need to implement a new method as popAt(int index) to make a pop operation on a specific … Read More »
In my solution, I used a structure with two traditional stacks. One of them is used to store the original elements. The other is used to store the latest minimum elements. At any time, the top element in the second … Read More »
I used a different solution from the ones in the original book. In the first official solution in the book, one stack might be full while another is empty. The space utilization is bad. In the second official solution, once … Read More »
There is a similar and easier question: how to check if an array is a palindrome? Or equivalently, how to check if a double linked list is a palindrome? The three solutions in the original question work well for these … Read More »
There is a follow up question: how to determine whether two linked lists, to say list1 and list2, intersect each other. Two solutions are available for this problem. On one hand, we could link the end of list1 to the … Read More »