I denne artikel vil vi diskutere den lineære søgealgoritme. Søgning er processen med at finde et bestemt element på listen. Hvis elementet er til stede på listen, kaldes processen vellykket, og processen returnerer placeringen af det element; ellers kaldes søgningen mislykket.
To populære søgemetoder er lineær søgning og binær søgning. Så her vil vi diskutere den populære søgeteknik, dvs. Linear Search Algorithm.
Lineær søgning kaldes også som sekventiel søgealgoritme. Det er den enkleste søgealgoritme. I lineær søgning går vi simpelthen hele listen igennem og matcher hvert element på listen med det element, hvis placering skal findes. Hvis matchen er fundet, returneres varens placering; ellers returnerer algoritmen NULL.
Det er meget brugt til at søge efter et element fra den uordnede liste, dvs. den liste, hvor elementer ikke er sorteret. Den værste tidskompleksitet ved lineær søgning er På).
De trin, der bruges i implementeringen af Lineær søgning, er angivet som følger -
- Først skal vi krydse array-elementerne ved hjælp af en til sløjfe.
- I hver iteration af for sløjfe, sammenligne søgeelementet med det aktuelle array-element, og -
- Hvis elementet matcher, skal du returnere indekset for det tilsvarende array-element.
- Hvis elementet ikke matcher, så flyt til næste element.
- Hvis der ikke er noget match, eller søgeelementet ikke er til stede i det givne array, returneres -1.
Lad os nu se algoritmen for lineær søgning.
Algoritme
Linear_Search(a, n, val) // 'a' is the given array, 'n' is the size of given array, 'val' is the value to search Step 1: set pos = -1 Step 2: set i = 1 Step 3: repeat step 4 while i <= 1 6 n step 4: if a[i]="=" val set pos="i" print go to [end of if] i="i" + loop] 5: 'value is not present in the array ' 6: exit < pre> <h2>Working of Linear search</h2> <p>Now, let's see the working of the linear search Algorithm.</p> <p>To understand the working of linear search algorithm, let's take an unsorted array. It will be easy to understand the working of linear search with an example.</p> <p>Let the elements of array are -</p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm.webp" alt="Linear Search Algorithm"> <p>Let the element to be searched is <strong>K = 41</strong> </p> <p>Now, start from the first element and compare <strong>K</strong> with each element of the array.</p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-2.webp" alt="Linear Search Algorithm"> <p>The value of <strong>K,</strong> i.e., <strong>41,</strong> is not matched with the first element of the array. So, move to the next element. And follow the same process until the respective element is found.</p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-3.webp" alt="Linear Search Algorithm"> <p>Now, the element to be searched is found. So algorithm will return the index of the element matched.</p> <h2>Linear Search complexity</h2> <p>Now, let's see the time complexity of linear search in the best case, average case, and worst case. We will also see the space complexity of linear search.</p> <h3>1. Time Complexity</h3> <table class="table"> <tr> <th>Case</th> <th>Time Complexity</th> </tr> <tr> <td> <strong>Best Case</strong> </td> <td>O(1)</td> </tr> <tr> <td> <strong>Average Case</strong> </td> <td>O(n)</td> </tr> <tr> <td> <strong>Worst Case</strong> </td> <td>O(n)</td> </tr> </table> <ul> <tr><td>Best Case Complexity -</td> In Linear search, best case occurs when the element we are finding is at the first position of the array. The best-case time complexity of linear search is <strong>O(1).</strong> </tr><tr><td>Average Case Complexity -</td> The average case time complexity of linear search is <strong>O(n).</strong> </tr><tr><td>Worst Case Complexity -</td> In Linear search, the worst case occurs when the element we are looking is present at the end of the array. The worst-case in linear search could be when the target element is not present in the given array, and we have to traverse the entire array. The worst-case time complexity of linear search is <strong>O(n).</strong> </tr></ul> <p>The time complexity of linear search is <strong>O(n)</strong> because every element in the array is compared only once.</p> <h3>2. Space Complexity</h3> <table class="table"> <tr> <td> <strong>Space Complexity</strong> </td> <td>O(1)</td> </tr> </table> <ul> <li>The space complexity of linear search is O(1).</li> </ul> <h2>Implementation of Linear Search</h2> <p>Now, let's see the programs of linear search in different programming languages.</p> <p> <strong>Program:</strong> Write a program to implement linear search in C language.</p> <pre> #include int linearSearch(int a[], int n, int val) { // Going through array sequencially for (int i = 0; i <n; i++) { if (a[i]="=" val) return i+1; } -1; int main() a[]="{70," 40, 30, 11, 57, 41, 25, 14, 52}; given array val="41;" value to be searched n="sizeof(a)" sizeof(a[0]); size of res="linearSearch(a," n, val); store result printf('the elements the are - '); for (int i="0;" < n; printf('%d ', a[i]); printf('
element is %d', (res="=" -1) not present in array'); else at %d position array', res); 0; pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-4.webp" alt="Linear Search Algorithm"> <p> <strong>Program:</strong> Write a program to implement linear search in C++.</p> <pre> #include using namespace std; int linearSearch(int a[], int n, int val) { // Going through array linearly for (int i = 0; i <n; i++) { if (a[i]="=" val) return i+1; } -1; int main() a[]="{69," 39, 29, 10, 56, 40, 24, 13, 51}; given array val="56;" value to be searched n="sizeof(a)" sizeof(a[0]); size of res="linearSearch(a," n, val); store result cout<<'the elements the are - '; for (int i="0;" < n; cout< <a[i]<<' cout<<'
element is '<<val; (res="=" -1) not present in array'; else at '<<res<<' position 0; pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-5.webp" alt="Linear Search Algorithm"> <p> <strong>Program:</strong> Write a program to implement linear search in C#.</p> <pre> using System; class LinearSearch { static int linearSearch(int[] a, int n, int val) { // Going through array sequencially for (int i = 0; i <n; i++) { if (a[i]="=" val) return i+1; } -1; static void main() int[] a="{56," 30, 20, 41, 67, 31, 22, 14, 52}; given array int val="14;" value to be searched n="a.Length;" size of res="linearSearch(a," n, val); store result console.write('the elements the are - '); for (int i="0;" < n; console.write(' ' + a[i]); console.writeline(); console.writeline('element is (res="=" -1) not present in array'); else console.write('element at +' position pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-6.webp" alt="Linear Search Algorithm"> <p> <strong>Program:</strong> Write a program to implement linear search in Java.</p> <pre> class LinearSearch { static int linearSearch(int a[], int n, int val) { // Going through array sequencially for (int i = 0; i <n; i++) { if (a[i]="=" val) return i+1; } -1; public static void main(string args[]) int a[]="{55," 29, 10, 40, 57, 41, 20, 24, 45}; given array val="10;" value to be searched n="a.length;" size of res="linearSearch(a," n, val); store result system.out.println(); system.out.print('the elements the are - '); for (int i="0;" < n; system.out.print(' ' + a[i]); system.out.println('element is (res="=" -1) not present in array'); else at +' position pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-7.webp" alt="Linear Search Algorithm"> <p> <strong>Program:</strong> Write a program to implement linear search in JavaScript.</p> <pre> var a = [54, 26, 9, 80, 47, 71, 10, 24, 45]; // given array var val = 71; // value to be searched var n = a.length; // size of array function linearSearch(a, n, val) { // Going through array sequencially for (var i = 0; i <n; i++) { if (a[i]="=" val) return i+1; } -1 var res="linearSearch(a," n, val); store result document.write('the elements of the array are: '); for (i="0;" i < n; document.write(' ' + a[i]); <br>' + 'Element to be searched is: ' + val); if (res == -1) document.write(' <br>' + 'Element is not present in the array'); else document.write(' <br>' + 'Element is present at ' + res +' position of array'); </n;></pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-8.webp" alt="Linear Search Algorithm"> <p> <strong>Program:</strong> Write a program to implement linear search in PHP.</p> <pre> <?php $a = array(45, 24, 8, 80, 62, 71, 10, 23, 43); // given array $val = 62; // value to be searched $n = sizeof($a); //size of array function linearSearch($a, $n, $val) { // Going through array sequencially for ($i = 0; $i < $n; $i++) { if ($a[$i] == $val) return $i+1; } return -1; } $res = linearSearch($a, $n, $val); // Store result echo 'The elements of the array are: '; for ($i = 0; $i < $n; $i++) echo ' ' , $a[$i]; echo ' <br>' , 'Element to be searched is: ' , $val; if ($res == -1) echo ' <br>' , 'Element is not present in the array'; else echo ' <br>' , 'Element is present at ' , $res , ' position of array'; ?> </pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/ds-tutorial/52/linear-search-algorithm-9.webp" alt="Linear Search Algorithm"> <p>So, that's all about the article. Hope the article will be helpful and informative to you.</p> <hr></n;></pre></n;></pre></n;></pre></n;></pre></=> Produktion
Program: Skriv et program til at implementere lineær søgning i PHP.
<?php $a = array(45, 24, 8, 80, 62, 71, 10, 23, 43); // given array $val = 62; // value to be searched $n = sizeof($a); //size of array function linearSearch($a, $n, $val) { // Going through array sequencially for ($i = 0; $i < $n; $i++) { if ($a[$i] == $val) return $i+1; } return -1; } $res = linearSearch($a, $n, $val); // Store result echo \\\'The elements of the array are: \\\'; for ($i = 0; $i < $n; $i++) echo \\\' \\\' , $a[$i]; echo \\\' <br>' , 'Element to be searched is: ' , $val; if ($res == -1) echo ' <br>' , 'Element is not present in the array'; else echo ' <br>' , 'Element is present at ' , $res , ' position of array'; ?> Produktion
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