# One Does Not Simply Solve 50 Hacker Rank Coding Challenges

Hey, It’s been a great** journey.** I started from **scratch**, and now I have **published** more than **50 blogs**. Each blog deals with **specific** questions from the** hacker rank **Coding challenges.

In this list, I am going to attach the **top** **50 blogs **and a** short** **description** of what that **blog **is all about. With the help of these 50 programs, You can also **achieve **a **gold badge **in the hacker rank** coding **challenges in the **Algorithms Section.**

I have published an ebook. A compilation of 100 Java(Interview) Programming problems which have been solved . I have given clear explanation and the code in the book. Believe me when I say, this will kick start you to achieve the job at your dream company.

Click on this **link** to get you to the landing page. It is completely free when you use kindle amazon. Take a look at it.

**I have also a series which is focused on top tech companies like Google, Amazon, Facebook, Quora, Youtube, Linkedin. etc, Take a look at that!**

Let’s go straight ahead to the problems that made me scratch my head and How I solved them.

**1) ****Hacker Rank Abridged**

This program was the inception of my **Blogging Career :). **This problem is nothing but a **Simple Array Sum**. The intention of this program is to find out the **sum **of the given **elements **in the** array. **And give you a** gist **on what we will be doing** throughout** this** journey**.

# 2) 2 Underlying principles for pattern printing

Uhm! **Pattern Printing** is the most** underrated **programming **logic** ever. There are **literally infinite **amount of **patterns** that could be** asked** in an **interview.** The** possibilities **for the **question **might be** infinite** but the **solution** could become** finite** if you know the **2 Principles** that** lurks** in the **shadows. **What are you waiting for then?** Click on the title**. To **shed light** on the **Principles.**

# 3) 1 Class for Handling copious data

Well well well, If you do not know this **Class **by now. You have to **make sure** that you make** yourself the time** to learn this** Class **and its **functions. **In various coding competition, This** Class **has come to **my aid** when I am put up against **Large** **numbers. **To find out What **this class **is all about, Click on the **Heading.**

# 4) Min Max Changeover

Consider finding the minimum and the max element to be the** pit stop **for any **Graders*.**Whenever they need a **refuel,** or when there is a slight **breakdown **in their system of questions. They would always rely on the **pit stop Crew**. Which is** led **by questions Covering** Minimum and Maximum **Elements. The **graders **of various **Competitions **would ask questions regarding this topic in a **convoluted** way, So that we the **programmers **do not **understand** that this is the question asked.

* A grader is someone who comes up with the question for interviews or coding challenges.

# 5) 3 variables for Plus Minus

This program introduces to the concept of **positive and negative** elements in the **array.** **Until** this** program,** We would have dealt with **only positive **numbers. From this program, We started to **write** programs for **negative** as well as** positive **elements also. This program** taught **us to** keep in mind **of the **constraints **that are** posed** in the question.

# 6) Mini-Max Sum

When you **drive straight** through the **tornado **(**programming world)**. You will be** lurched** around various** structures. **From **loops to complex data structures. **But A certain** Structure **which could **remain rigid **throughout the **thunderstorm **is the one that **envelops** all these **complex structures,** which is the** Simple If-else Structure**. **Remove** the **Efficiency factor,** Most of the **Programs** can be solved using **simple if-else** statements.

# 7) 2 Variables to solve a Triplet

This program introduces the user to the topic of **if else** structures. This deals with how you **delineate** an **if condition** based on the **given stipulation**. You have to **compare **and** find out** the** points** that has to be given to the** winner.**

# 8) 5 variables for Birthday Cake Candles

This program deals with finding the **maximum element** present in the **array.** You would be **surprised**, how most of the** problems** require us to** find **the **maximum **element in the **array**. It is a **must** for a** programmer** to know the **logic** behind, Finding out the maximum or minimum element in an array.

# 9) Hacker Rank-An alternative solution to Grade Students

This program deals with **grading students** based on the given** stipulations. **This is how most of the **grading system** works in most of the colleges. There will be** more constraints** in real life. But, here it is simplified more, With **only one** stipulation.

# 10) 1 Traversal for 2 Diagonals

This program gives you a** different outlook** in solving **a problem**. While Solving this program, I wanted to **reduce **th**e number of loops** from the **original source code**. Since it takes up **too much** time for **repeating **the same steps. So, I reduced the number of loops, to **solve **this program with **only one** **loop.**

# 11) How to Spot Implied Conditions?

**To Be honest,** Implied Conditions are **present **in most of the **questions.** And they **do not affect **the result, even if it goes **unnoticed** by the programmer. But Certain problems, such as **this one** will give you a** twirl. **If you let the **Condition** get **overlooked. **So I would like you to go through this program to **understand **what an** Implied Condition** is. And **make sure **that you won’t be **disregarding** the importance of **Implied Condition **in your **next Interview.**

# 12) A look into Nested loops problem-Divisible Sum Pair

Well, Here comes the structure which is **Second only **to** If-else Structure. **The **Nested Loop **Structure. Nested Loops **help **the programmers,** Solve** the problems while **traversing** for the** first time** itself. Rather than having to go through all the **array iteratively . **And **saves **us from **repeatedly writing **different loops** to **do the** same thing** over and over again. This program marked the **beginning** of using **nested loops **instead of solving through** if-else structures.**

# 13) Can you solve while reading the array for the first time?

This program gives you a **different perspective** while handling a problem. This poses the **question** whether you could solve a problem while **reading for the values** itself. If we can solve a problem while the user e**nters the data **into the array itself. It** reduces Computational Time** and also reduces the **Memory Storage. **I would ask you to **go through** this **program** at least **once. **Because, This would give the** insight **for you in **reducing the number of lines** with which you **code**.

# 14) Approaching Window Sizes problem- Birthday Chocolate.

Oh, Yes. Window Sizes Problem are one of the **tough logic** to **encounte**r. But When **learn**t, It will **aid **you in **solving** problems that involve anything in the range of** Permutations **and** Combinations.** **Permutations **within the array can be** encountered **using** Window Sizes Problem **only. Each window has different **lengths. **Starting from **[1 … n].**

# 15) Brute Force?

If you had been **following **my **blog posts,** You would know How much I am interested in** Solving** a particular **Problem** Using **Mathematical Equations**. It is an **understatement **to say that** Math **plays a **role** in everybody’s **life. Mathematical Equations** aids the programmer in **replacing **the** complex structures** with **Simple equations**. It does** Save **us a lot of** Code Space**.

# 16) 1 Variable Solving Bon Appétit

This problem is nothing but a** simple array sum **with some more calculations such as **subtraction. **This program deals with the **intertwining** of array **sum **and **subtraction **of certain elements from the** array. **And the catch is that we use only **one variable **to do all these **calculations.**

# 17) What is Cleft Problem Solving?

Ooh, You have to Know about this **problem Solving **Technique. It **kind of **resembles the **Divide and Conquer Approach.** But it **varie**s from this **approach **in a way that there can be **two or more outcomes **based on the content present in the **input. Cleft Problem Solving **will come** handy **to you when the** outcome varies** when the** input varies.**

# 18) Nested if-else to solve Library Fine

Apart from the** if-else structure**. It could get a** slightly complex **but the **result **would be much more **detailed**. That is th**e strong suit **of** nested** if else structure.

# 19) 2 variables Solving Migratory birds

This is also a **min- max problem**. The only **difference **from its predecessor is that** instead** of checking **for the value** directly. We have to find out the **occurrences **of each element in the **array.** And Produce the **output **which deals with the **maximum** of the elements that are **occurring repeatedly.**

# 20) Can Dummy values Expedite Solving??

Dummy values are **temporary changes** in the given input. There are certain problems, which involves in **inputs** after **visiting once**, it becomes **redundant. **These inputs **if not** changed will change the **after effect **of the **problem. **In order to** ensure **that there are** no changes** in the** outcome** due to these **redundant **variables. You have to know about **dummy values. **But The** answer** to the question whether dummy values **expedite** the process of **solving,** rests in you to** find out **by clicking **on the Title :).**

# 21) Pair sum with an additional twist

This is the **Second program** which uses** nested loops** for the solution. The twist is in the sense that a **normal array sum** can be mixed with a **nested loop **structure and the **problem **could make you **miserable.**

# 22) A Cat and Mouse Game

This is a **simple game** which decides the** fate of the mouse.** It could either **end up** in the Mouse getting **Triumphant**. Or it could end in** Horror stricken **end for the** Mouse**. We have to** predict **the **outcome** from the given input. This program aids you in understanding the** need of the ABS **function in **Math** class in **Java.**

# 23) How a simple sort expedites the outcome!

The use of **Sorting Algorithms, **Only when a sort is** required or mentioned** in the question is a **bland** way of using the **sort function. **A **Well-Known** Fact about **Sorting **is that it can be used to solve various problems. At the **beginning** itself. Use this **tip **in solving various problems. If there is a **chance **for **sorting**, There is a **possibility** that it can be solve with **efficiency.**

# 24) 2 Indices solving Minimum Distances

This program asks us to find out the distance between two same numbers present in the array. And find out the minimum distance between two such element. Instead of using **O(n²) naive approach. **We could solve it in **O(n). This is the answer for the previous blog. **How a **simple sort changes** the **O(n²) **approach to** O(n).**

# 25) Solving hurdle Race

Well This **serving** is a mixture of **Implied Conditions** and **Min max **problems **saute** together and served in a** platter **of** illusive sentences**. Here, We find the application of the **implied conditions** that I have talked** earlier** in the 11th Blog. You would find why this is **important**, When you go through this **program.**

# 26) A twist in normal product!

In this problem, you will find out the question is **represented **in a **convoluted **way. It’s intention is to make you **digress** from the** answer** which is **right in front of you. **It is a normal **Multiplication **problem, but when you** pore over **the question, I am **confident** that You will **figure o**ut the reason.

# 27) 1 variable to solve Angry Professor

This problem is what you would call a **counting problem**. It’s **crux** is that it requires some** number of elements **based on a **certain Stipulation**. Counting problem’s are **widespread** from **counting** the **elements** in an **array** to **Counting the next greater element **present for a **certain element **within the array. This program is the **commencement** of the various **counting problem **which we will **come across later.**

# 28) Problem for Advertising and gathering Likes!

Okay, From this problem **onward**. You should be **knowing** the **basic functions **in **Math Class.** To **assist** you with this, This program deals with the **rounding off** functions in** Math Class in Java**. They are **Floor and Ceil** functions. Flooring and Ceiling** Functions** are required when you **convert** a **double or float** variables into an **integer. After **this program**, **you will be able** to boost your abilities **in Solving problems using **Math Class** in Java.

# 29) Linear Search Solves Sequence Equation

As the name suggests, We are dealing with a Linear Search Algorithm. This is search Algorithm which works under **O(n). **It helps the programmer to find the specific element from the given sequence.

# 30) Must know logic in Problem Solving

We are going through one of the **most referred logic **in solving problems. They are** Reversing** the** value of a number.** At the first look, it’s **simple. **Because we are thinking to solve it in a **non programmatic way. **Actual reversing of digits requires **Multiplication and Modulo Operations **done in a sequence to get the **reversal right**. The following program helps you in gathering** knowledge **about** reversing** a digit.

# 31) Solving Fair Rations in O(n)

**O(n) **traversal represents the **fact** that the **answer **could be produced with only one traversal through the whole array. This problem introduces you to the concept of **O(n) traversals.**

# 32) What are flag variables?

Next to **dummy values,** That are used when there is **no use **of that variable after a **single traversal**. Flag variables are something **different**, they are **decision making **variables that comes to the **rescue** when a **cleft problem solving** is involved. The decision to** print a yes or no **will eventually depend on the **value** of a **flag variable.** Do learn about **flag variables** by clicking on **the title.**

# 33)Utopian Tree Conundrum

**Never forget the basics**. This is why this **simple if-else **problem has come up in this position. After delving deep into c**omplex nested loops** and** sorting functions.** It is **refreshing **to solve a simple problem with an **if-else** structure. So that,This does not **overload **your brain.

# 34) Max function to Solve Halloween Sale

Well Max and min problems are present in most of the coding competitions. Only that they are disguised in question as something else. When you read through this question you will understand the reason.

# 35) The Brute Force II?

As I have told earlier, **Mathematical Equations** aids the programmer in **replacing **the** complex structures** with **Simple equations**. It does** Save **us a lot of** Code Space**. This program is another such **example**, where A **hefty programming logic **can be overcome with the help of a **simple mathematical equation. **Mathematical equations are a** blessing** for us** programmers**. You will come to** extrapolate **when you have gone through this **logic.**

# 36) Passing through the valley of codes

This **embarked **my journey into **Strings. **Most of the** problems **that I come across which uses **String** as an Input. I **convert** them into a **character array **and Solve them. I don’t know why, But I found this** approach **way more **comfortable** to me. Instead of Using **Pre-defined **Functions. Maybe, The **experience **that you **gain** when You** get to write** your **own functions** is the **reason** behind my s**heltered outlook**. You could** peruse the contents **and tell me, Which **approach** You find **amusing**. I would** cherish** your **responses.**

# 37) 1 Variable solving Jumping on the clouds

This is also a **counting **Problem. Here we have to find out the the** minimum number of jumps** required to reach the end. Whenever 1 variable can be used to solve a program then it is a **counting **Problem.

# 38) Everyone must Know 1 Sort!!

I always ask a** programmer **who is** starting** his **career** as a **coder**. To learn **one sorting** algorithm. And it has to be in his **fingertips**. He should not **waste **time in **writing a code** for sorting function when he should be **outstripping **the problem in hand. No matter what the **sorting algorithm** is, **Take one **and **understand **the logic. Whenever asked to **write a sort function**. You should be able to come up with **that logic.**

**39)**Big Integer to the Rescue!

This Class has **never let me** down, when it comes to** solving problems**, that handles** large values.**To find out What **the functions in this class **is all about, Click on the **Heading.**

# 40) Want to know the major player in any Programming language?

As I have told earlier, **Mathematical Equations** aids the programmer in **replacing **the** complex structures** with **Simple equations**. It does** Save **us a lot of** Code Space.** They are the best way of representing **100 lines **of code in a **single equation**. Here is** another blog** which deals with **solving a program mathematically**. Math makes our **lives easier**. Math makes our **code simpler.**

**41) ****Nested if-else to solve Taum and B’day**

Apart from the** if-else structure**. It could get a** slightly complex **but the **result **would be much more **detailed**. That is th**e strong suit **of** nested** if else structure.

# 42) 1 variable Solving Triplets

This is also a **counting** problem. The problem asks us to **find out **the number of **triplets.** That equal the value of **d. **we could **solve **this problem in **O(n³). **In order to reduce the** number of traversals**. We introduce a **new condition**. By doing so, we could **reduce the number **of **traversals **significantly.

# 43) O(n) extra space for Equalizing the array

This problem introduces us to the concept of **increasing the memory** space to increase the **efficiency of solving **the problem. This program does** increase the extra space** and **increases the speed **in which the problem is **solved.** Read through **the code **to **understand** the logic.

# 44)Where to Use Hash Maps?

Well till now, We have **not used a**ny of the **complex data structures.** Hash Maps are not complex but are very useful when it comes down to **String retrieval Problems**. Whenever a **dictionary resembling **data structure is **required **you have to solve it using **Hash Maps.** **When and Where **to use hash maps is what this** particular blog** deals about.

# 45) How to Splinter Number into Digits!

**Splintering Number** into** digits** is the process of **separating** each** digit **from a **number.** Like the **reversal** of a number, This** programming logic** has also been asked in **various coding competitions. **This kind of logic would be a **pre-requisite** in solving various problems. **(i,e) **The **answer** would **not **be **found** after **splintering **is done. You have to** perform certain operations** on the **splintered digits** and then you have to** produce the output.**

# 46) 1 Variable Solving Chocolate Feast

Whenever **1 variable** is used to **solve the problem.** It is a **counting problem**. The problem has asked us to find out the **number **of chocolates that user eats by e**xchanging the wrappers. **In **counting problems**, it is important to know what you are going to** count.** This will be mostly present in the** question**. But sometimes it might end up as** implied conditions. **Watch out for these type** **of questions.

# 47) Solving circular array rotation

Certain programs, ask you to do the same set of** basic work,** over and over again. If you introduce a** loop **that does this **basic set of operations **repeatedly. It might result in a** Run time Error**. In order to **avoid this**, we must r**educe the number of time**s the **basic operations** are done. This can be done by **finding out **certain **logic** that can **abate **the number of operations. This **program **helps you in **how to find such logic.**

# 48)How a bland min function can become a buzz?

Sometimes, The** creators** for coding challenges **disguise** a **simple** answer with a **complex question** lining. The problem might create** distractions**, So that you would be left **confused.** But the answer would have been **right next **to you, and you would not have noticed. The problem mentioned below does **just this. **You could find more about by perusing through the** explanation **and **algorithm.**

# 49)Flag variable Solving Flatland Space Stations

This problem deals with the **flag variables **and** min max problems. **lag variables are something **different**, they are **decision making **variables that comes to the **rescue** when a **cleft problem solving** is involved. The decision to** print a yes or no **will eventually depend on the **value** of a **flag variable.**

# 50) 2 variable Solving ACM ICPC

This is a combination of **min max, counting **and **String retrieval problem. **This is the final program of the 50 blog series. After solving all these problems in **hacker rank **you will receive a **gold badge** in the algorithms section. This is what I **had worked** for.

**Conclusion**

Well guys, I thank you for all your** support**. Past few days have been **boorish. I live by the motto **Anybody could** code.** All it takes is some** hard work**. And a **guide** to clear your doubts. Without the help of **my mento**r, I would not be able to become a **coder. **He **cleared** my doubts whenever I had them. And He will not give the **answer directly **but he will make **you understand** the logic **behind **the question.

Whenever you guys have a** doubt,** regarding these** problems.** Share your **Thoughts** with me. I would do **my best** to clear those** doubts.**

No **Single Solution** exists to a problem.**Work **on the Code. These problems are from HackerRank.

You can **follow House of Codes **to receive updates when we post new coding challenges. Also you could send us your** solutions **or your** ideas **for any coding challenge. We would be **thrilled** to read them. :)