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  1. Getting Started with Algorithm
    What is an Algorithm?
  2. Characteristics of Algorithm
    1 Topic
  3. Analysis Framework
  4. Performance Analysis
    3 Topics
  5. Mathematical Analysis
    2 Topics
  6. Sorting Algorithm
    Sorting Algorithm
    10 Topics
  7. Searching Algorithm
    6 Topics
  8. Fundamental of Data Structures
  9. Queues
  10. Graphs
  11. Trees
  12. Sets
  13. Dictionaries
  14. Divide and Conquer
    General Method
  15. Binary Search
  16. Recurrence Equation for Divide and Conquer
  17. Finding the Maximum and Minimum
  18. Merge Sort
  19. Quick Sort
  20. Stassen’s Matrix Multiplication
  21. Advantages and Disadvantages of Divide and Conquer
  22. Decrease and Conquer
    Insertion Sort
  23. Topological Sort
  24. Greedy Method
    General Method
  25. Coin Change Problem
  26. Knapsack Problem
  27. Job Sequencing with Deadlines
  28. Minimum Cost Spanning Trees
    2 Topics
  29. Single Source Shortest Paths
    1 Topic
  30. Optimal Tree Problem
    1 Topic
  31. Transform and Conquer Approach
    1 Topic
  32. Dynamic Programming
    General Method with Examples
  33. Multistage Graphs
  34. Transitive Closure
    1 Topic
  35. All Pairs Shortest Paths
    6 Topics
  36. Backtracking
    General Method
  37. N-Queens Problem
  38. Sum of Subsets problem
  39. Graph Coloring
  40. Hamiltonian Cycles
  41. Branch and Bound
    2 Topics
  42. 0/1 Knapsack problem
    2 Topics
  43. NP-Complete and NP-Hard Problems
    1 Topic
Lesson 7, Topic 1
In Progress

Linear Search

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Linear search is a very basic and simple search algorithm. In Linear search, we search an element or value in a given array by traversing the array from the starting, till the desired element or value is found.

Implementing Linear Search

Following are the steps of implementation that we will be following:

  1. Traverse the array using a for loop.
  2. In every iteration, compare the target value with the current value of the array.
    • If the values match, return the current index of the array.
    • If the values do not match, move on to the next array element.
  3. If no match is found, return -1.

To search the number 1 in the array given below, linear search will go step by step in a sequential order starting from the first element in the given array.

KodNest Capture3

Start from the first element, compare k with each element x.

KodNest Capture4

If x == k, return the index.

KodNest Capture5

Else, return not found.

Linear Search Algorithm

LinearSearch(array, key)
  for each item in the array
    if item == value
      return its index

Linear Search Program in C

// Linear Search in C

#include <stdio.h>

int search(int array[], int n, int x) {
  // Going through array sequencially
  for (int i = 0; i < n; i++)
    if (array[i] == x)
      return i;
  return -1;

int main() {
  int array[] = {2, 4, 0, 1, 9};
  int x = 1;
  int n = sizeof(array) / sizeof(array[0]);

  int result = search(array, n, x);

  (result == -1) ? printf("Element not found") : printf("Element found at index: %d", result);

Linear Search Complexities

Time Complexity: O(n)

Space Complexity: O(1)

Linear Search Applications

  1. For searching operations in smaller arrays (<100 items).

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