“A sequential solution to a problem written in human language.“
- The algorithm is the first step of the solution process after the analysis of the problem, programmers write the algorithm of that problem.
- An algorithm is a finite sequence of instructions, logic, and explicit step by step procedures for solving a problem.
- The number of instructions should be finite.
- Order is important when it comes to instructions.
Rules for Write the Algorithm Step by Step
You must know how to solve a problem before you can write an algorithm. The solution must make sense.
- In order to solve a problem, you must identify all inputs and outputs.
- Add the necessary data and constants.
- Steps in the computation.
- You can print / display all the results.
Qualities of a Good Algorithm
- Both input and output must be clearly defined.
- Each step in an algorithm should be clear and unambiguous.
- In most cases, the algorithm is the best way to solve a problem.
- Program code is not part of an algorithm.
- An algorithm should be written so that it can be used in other programming languages.
Where Do We Use Algorithm?
- To find the best route to take (Google Map).
- (Chess) Making games that can defeat us in them.
- We can buy some products online and pay for them while sitting in our home and many more (almost everywhere).
Example to write the Algorithm step by step
Live Example 1:
Write an algorithm To make a coffee.
| Steps | Instructions |
|---|---|
| Step 1 | Take a pot, add the proper amount of water. |
| Step 2 | Place the pan on a gas stove and lights it. |
| Step 3 | As soon as it boils, add the coffee powder. |
| Step 4 | Add enough sugar and milk to taste. |
| Step 5 | Put it in the cup and drink it. |
Example 2:
Write an algorithm to add two numbers entered by the user.
| Steps | Instructions |
|---|---|
| Step 1 | Start. |
| Step 2 | Define num1, num2, and sum. |
| Step 3 | Ask the user to enter two numbers. |
| Step 4 | We will read values num1 and num2. |
| Step 5 | The sum will be calculated once num1 and num2 are added. sum ← num1 + num2 |
| Step 6 | Display sum. |
| Step 7 | Stop. |
Algorithm Patterns
- Following are three major patterns of algorithms:
- Sequential
- The steps describe how each step occurs.
- For Example:
- Create an algorithm to find the sum of any two numbers.
- Write an algorithm to find the volume of a cylinder.
- Conditional
- An instruction may be divided based on more than one condition.
- For Example:
- Write an algorithm to check whether a given number is even or odd.
- Write an algorithm to find out a voter’s eligibility based on her/his age.
- Iteration
- There is more than one repetition of the same set of instructions.
- For Example:
- Write an algorithm to print all the even numbers between 1 to 10.
- Write an algorithm to print all the odd numbers between 1 to 10.
- Sequential
Example 3:
Write an algorithm to find the largest among three numbers.
| Steps | Instructions |
|---|---|
| Step 1 | Start. |
| Step 2 | Declare variables a, b and c. |
| Step 3 | Read values a, b and c. |
| Step 4 | If a>b If a>c Display a is the largest number. Else Display c is the largest number. Else If b>c Display b is the largest number. Else Display c is the largest number. |
| Step 5 | Stop |
Types of Algorithm
Divide and Conquer Algorithm
- The divide and conquer algorithm works by repeatedly breaking down a problem into two or more smaller problems of the same or related type until the problems are simple enough to solve directly.
- For Example
- Merge Sort
- Quick Sort
- Binary Search
Backtracking Algorithm
- Backtracking is a method to find a solution to a problem step by step.
- It approaches problems recursively and tries to solve one piece of the problem at a time in order to find its solution.
- If one of the solutions fails, we discard it and try another one.
- In other words, a backtracking algorithm solves a sub problem and, if it fails to do so, undoes the last step and tries again to solve the problem.
- For Example
- N Queen Problem
Brute Force Algorithm
- There are many algorithms in this concept, but this is one of the simplest.
- An algorithm that uses brute force iterates through all the possible solutions to find at least one that can solve the problem.
- For Example
- Selection Sort
Greedy Algorithm
- These algorithms solve optimization problems.
- By applying this algorithm, we can derive a local optimum solution (without considering any implications in the future) and then hope to find the global optimum solution.
- The method does not guarantee that we will be able to find an optimal solution.
- For Example
- Huffman Coding and Diijkstra’s Algorithm
Dynamic Programming Algorithm
- In this technique, the main focus is on the speed of execution rather than the amount of memory used.
- In other words, a dynamic programming algorithm solves complex problems by breaking them into simple subprograms, and then it solves each of them once and then stores them for a future case.
- As a result of these algorithms, they will use the results of previous runs to find new ones.
- For Example
- Fibonacci Series
Recursive Algorithm
- An algorithm that calls itself until it solves the problem.
- For Example
- Tower of Hanoi
Conclusion
If you liked this article, you may also be interested in these topics: