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- This guide breaks down 15 essential Coding Problems in DSA, covering everything from loops and arrays to recursion and linked lists.<\/li>\n\n\n\n
- Each problem is explained in plain terms, so you understand the logic before jumping into code.<\/li>\n\n\n\n
- A quick reference table lists every problem along with its category, difficulty level, and the core concept it teaches.<\/li>\n\n\n\n
- The Coding Problems in DSA are grouped by topic, making it easy to focus on one area at a time, like sorting, searching, or patterns.<\/li>\n\n\n\n
- By the end, you’ll have a clear starting point for practicing Coding Problems in DSA and building real problem-solving skills.<\/li>\n<\/ul>\n\n\n\n
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Key Concepts to Master for Solving DSA Problems<\/strong><\/h2>\n\n\n\n
![\"\"](\"https:\/\/www.guvi.in\/blog\/wp-content\/uploads\/2025\/12\/01@2x-1-2-1200x630.png\" "\\"\\"")
<\/figure>\n\n\n\nBefore indulging in solving DSA<\/strong><\/a> problems, you need a solid understanding of essential topics. Start by gaining a firm grasp of input and output programs and, simultaneously, practice questions on loops<\/a> and conditional statements to develop a fundamental understanding of how the logic flows during program execution. <\/p>\n\n\n\n
Then move on to array and string<\/a> problems, which will help you handle and manage data efficiently. After that, you should explore basic search and sorting methods, such as linear search and bubble sort.<\/p>\n\n\n\n
Once you’ve completed all this, try tackling simple recursion<\/a> problems and pattern-based<\/a> printing to strengthen your analytical thinking. <\/p>\n\n\n\n
As you progress, start learning other data structures, such as stacks, queues, and linked lists, as well as math-based topics like numbers, factorials, and palindromes. These are key concepts to master for solving DSA problems.<\/p>\n\n\n\n
Note: <\/strong>We use JavaScript <\/strong>as the primary language to explore the following fundamental DSA problems. You can also use other programming languages, such as C++<\/a>, Java, or Python<\/a> (the logic is the same across <\/em><\/span>languages; only the syntax differs)<\/em>.<\/p>\n\n\n\n
Strengthen your programming skills with our comprehensive and affordable HCL GUVI’s DSA course<\/em>: <\/strong>DSA for Programmers Course<\/a><\/p>\n\n\n\n
<\/p>\n\n\n\n
Ready to build real projects? The HCL GUVI’s <\/em><\/strong>Software and AI Engineer Course<\/a><\/em> teaches DSA, full stack development, and AI-powered workflows through hands-on projects, expert mentorship, and mock interviews, everything you need to turn practice problems into a job-ready portfolio. Enroll now and start building.<\/em><\/strong><\/p>\n\n\n\n
<\/p>\n\n\n\n
List of Basic Coding Problems in DSA for Beginners<\/strong><\/h2>\n\n\n\n
The following are the fundamental coding problems in DSA we have mentioned, along with the category to which each belongs:<\/p>\n\n\n\n
1. Print all prime numbers within a given range (Loops and Conditionals)<\/em><\/strong><\/h3>\n\n\n\n
Check every number in the range and print only the ones that can’t be divided evenly by anything except 1 and themselves.<\/p>\n\n\n\n
function PrimesInRange(start, end) {\n\n for (let num = start; num <= end; num++) {\n\n let isPrime = true;\n\n if (num < 2) continue; \/\/ 0 and 1 are not prime\n\n for (let i = 2; i * i <= num; i++) {\n\n if (num % i === 0) { \n\n isPrime = false;\n\n break;\n\n }\n\n }\n\n if (isPrime) {\n\n console.log(num);\n\n }\n\n }\n\n}\n\nPrimesInRange(10, 30);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
11\n\n13\n\n17\n\n19\n\n23\n\n29<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
In this code, the function traverses every number in the given range sequentially to check whether it is divisible by any number from 2<\/strong> to its square root. If a given input number has no divisors<\/strong>, it is considered prime\u00a0<\/span>and printed to the console; otherwise, the loop exits, terminating the operation.<\/p>\n\n\n\n
Explore:<\/strong> Can I Get a Developer Job Without DSA? The Truth From 50+ Hired Developers<\/a><\/p>\n\n\n\n
2. Find the sum of digits of a number (Loops and Conditionals)<\/em><\/strong><\/h3>\n\n\n\n
Break the number into individual digits and add them all together.<\/p>\n\n\n\n
function sumTotalOfDigits(num) {\n\n let sum = 0;\n\n while (num > 0) {\n\n let digit = num % 10; \/\/ extract last digit\n\n sum += digit; \/\/ add it to sum\n\n num = Math.floor(num \/ 10); \/\/ remove last digit\n\n }\n\n console.log(sum);\n\n}\n\nsumTotalOfDigits(9876);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
30<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
Observe the modulus operator % 10<\/strong> here; it is included in this code to repeatedly extract the last digit of a number and add it back to a sum variable (which in this case is initialized to 0<\/strong>). <\/p>\n\n\n\n
Once that is done, we move on to the next line, where we remove the last digit by dividing by 10<\/strong>, then use a built-in Math method to round it down to the nearest integer. This process continues until the number becomes 0<\/strong>. And at last, we get our resultant sum of all digits.<\/p>\n\n\n\n
3. Find the second largest element in an array (Arrays and Strings)<\/em><\/strong><\/h3>\n\n\n\n
Go through the array once and keep track of the largest and second largest values as you compare each element.<\/p>\n\n\n\n
function secondLargestNumber(arr) {\n\n if (arr.length < 2) {\n\n console.log(\u201cInvalid, number should contain at least 2 digit.\u201d);\n\n return;\n\n }\n\n let firstNum = -Infinity;\n\n let secondNum = -Infinity;\n\n for (let num of arr) {\n\n if (num > firstNum) {\n\n second = firstNum;\n\n firstNum = num;\n\n } else if (num > secondNum && num < firstNum) {\n\n secondNum = num;\n\n }\n\n }\n\n console.log(secondNum);\n\n}\n\nsecondLargestNumber([10, 40, 30, 50, 20]);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
40<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
Here, the ‘for of’ <\/strong>loop is used to traverse through each element in the array<\/a><\/strong> to keep track of the largest and second most significant numbers. The logic flows like this:<\/strong> if an<\/span> element is larger than the current largest number<\/strong> in the array, it updates both<\/strong> the largest and the second-largest numbers.<\/p>\n\n\n\n
If it’s between the largest and the second-largest<\/strong>, it updates only <\/strong><\/span>the second-largest. This way, the function effectively finds the second-largest element without unnecessary steps.<\/p>\n\n\n\n
4. Reverse a string without using built-in functions (Arrays and Strings)<\/em><\/strong><\/h3>\n\n\n\n
Swap characters from the start and end of the string, moving toward the middle, until the whole string is flipped.<\/p>\n\n\n\n
function reverseString(str) {\n\n let result = \u201c\u201d;\n\n for (let i = str.length \u2013 1; i >= 0; i\u2013) {\n\n result += str[i];\n\n }\n\n console.log(result);\n\n}\n\nreverseString(\u201chello\u201d);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
olleh<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
In this example, we run the for loop<\/strong> starting from the last character of the string<\/strong>, so we can iterate backwards<\/strong> and build a new <\/span>string by adding each character in reverse order<\/strong>. This function traverses the string from end to start and appends each character, producing the reversed string as output.<\/p>\n\n\n\n
5. Implement Linear Search (Searching)<\/em><\/strong><\/h3>\n\n\n\n
Check each element one by one until you find the value you’re looking for.<\/p>\n\n\n\n
function linearSearchOperation(arr, target) {\n\n for (let i = 0; i < arr.length; i++) {\n\n if (arr[i] === target) {\n\n console.log(`Element ${arr[i]} found at index ${i}`);\n\n return;\n\n }\n\n }\n\n console.log(\u201cElement doesn\u2019t exist.\u201d);\n\n}\n\nlinearSearchOperation([5, 8, 2, 9, 1], 9);\n\n\/\/and\n\nlinearSearchOperation([5, 8, 2, 9, 1], 4);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
Element 9 found at index 3\n\nElement doesn\u2019t exist. \/\/ 4 is not present in the array<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
The search operation begins by checking each element of the array<\/strong><\/a> in sequence to determine whether any matches the target value<\/strong>. If a match is found<\/strong>, it prints the corresponding element along with its index. And if the loop completes without finding the target element<\/strong>, it prints that the number doesn’t exist.<\/p>\n\n\n\n
6. Implement Binary Search on a sorted array (Searching)<\/em><\/strong><\/h3>\n\n\n\n
Repeatedly divide the sorted array in half to quickly narrow down where the value is.<\/p>\n\n\n\n
function binarySearchOperation(arr, target) {\n\n let left = 0;\n\n let right = arr.length \u2013 1;\n\n while (left <= right) {\n\n let mid = Math.floor((left + right) \/ 2);\n\n if (arr[mid] === target) {\n\n console.log(`Element ${arr[mid]} found at index ${mid}`);\n\n return;\n\n }\n\n else if (arr[mid] < target) {\n\n left = mid + 1;\n\n }\n\n else {\n\n right = mid \u2013 1;\n\n }\n\n }\n\n console.log(\u201cElement not found inside the given array.\u201d);\n\n}\n\nbinarySearchOperation([2, 5, 8, 12, 16, 23, 38, 56], 23);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
Element 23 found at index 5<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
Binary search is an algorithm that divides<\/strong><\/a> a sorted array in half to check whether the element matches the target value; this process repeats<\/strong> until the element is found or the array length becomes 1, indicating there is no more space left to search. <\/p>\n\n\n\n
If the target is smaller than the middle <\/strong><\/span>element<\/strong>, it continues searching in the left half<\/strong>; if it is larger, it searches in the right half<\/strong>. And in this way, the search process becomes much faster than the linear search for sorted arrays, because in each loop, we traverse only half the previous array size<\/strong>.<\/p>\n\n\n\n
7. Sort an array using Bubble Sort (Sorting)<\/em><\/strong><\/h3>\n\n\n\n
Compare pairs of neighboring elements and swap them if they’re in the wrong order, repeating until the array is sorted.<\/p>\n\n\n\n
function bubbleSortingNumbers(arr) {\n\n let n = arr.length;\n\n for (let i = 0; i < n \u2013 1; i++) {\n\n for (let j = 0; j < n \u2013 i \u2013 1; j++) {\n\n if (arr[j] > arr[j + 1]) {\n\n \/\/ swapping elements with each other\n\n let temp = arr[j];\n\n arr[j] = arr[j + 1];\n\n arr[j + 1] = temp;\n\n }\n\n }\n\n }\n\n console.log(\u201cResultant array in sorted order:\u201d, arr);\n\n}\n\nbubbleSortingNumbers([64, 34, 25, 12, 22, 11, 90]);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
Resultant array in sorted order: [11, 12, 22, 25, 34, 64, 90]<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
In this code, the function sorts the <\/a>array<\/strong><\/a> by repeatedly comparing adjacent <\/strong><\/span>elements <\/strong>and swapping<\/strong> them if they are out of order. With every single loop execution, the biggest unsorted element bubbles up to the end of the array. And after completion of all loop runs, the input arrays get sorted in ascending order.<\/p>\n\n\n\n
8. Sort an array using Insertion Sort (Sorting)<\/em><\/strong><\/h3>\n\n\n\n
Take each element and insert it into its correct position among the already sorted elements before it.<\/p>\n\n\n\n
function insertionSorting(arr) {\n\n for (let i = 1; i < arr.length; i++) {\n\n\n let key = arr[i];\n\n let j = i \u2013 1;\n\n\/\/ Move the elements that are greater than the key element one position ahead\n\n while (j >= 0 && arr[j] > key) {\n\n arr[j + 1] = arr[j];\n\n j\u2013;\n\n }\n\n arr[j + 1] = key;\n\n }\n\n console.log(\u201cResultant array in sorted order\u201d, arr);\n\n}\n\ninsertionSorting([12, 11, 13, 5, 6]);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
Resultant array in sorted order: [5, 6, 11, 12, 13]<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
In this example, the function begins by treating an element as a key<\/strong> and placing it in the correct position among the already sorted<\/strong><\/span> elements on the left<\/strong>. It does this by gradually shifting all larger array elements to the right <\/strong>to make<\/span> space for the key element. After repeating this process for every element, the input array gets sorted and printed to the console.<\/p>\n\n\n\n
9. Find the factorial of a number using recursion (Basic Math and Number Problem)<\/em><\/strong><\/h3>\n\n\n\n
Multiply the number by the factorial of the number just below it, repeating until you reach 1.<\/p>\n\n\n\n
function findFactorial(n) {\n\n let result = 1;\n\n for (let i = 1; i <= n; i++) {\n\n result *= i;\n\n }\n\n console.log(result);\n\n}\n\nfindFactorial(6);<\/code><\/pre>\n\n\n\nOutput:<\/em><\/strong><\/p>\n\n\n\n
720<\/code><\/pre>\n\n\n\nExplanation:<\/em><\/strong><\/p>\n\n\n\n
A factorial is the product of all the positive integers less than the given number, including itself. Here, we have calculated the factorial by multiplying the result variable by each number from 1 to the n parameter using a loop<\/strong>. After the loop completes, the result stores the final product value, which is printed to the console.<\/p>\n\n\n\n