Count consecutive pairs of same elements - GeeksforGeeks

03 Jun, 2021
Given an array arr[], the task is to count the number of pairs formed by consecutive elements in which both of the elements in a pair are same.Examples:  
Input: arr[] = {1, 2, 2, 3, 4, 4, 5, 5, 5, 5} Output: 5 (1, 2), (4, 5), (6, 7), (7, 8) and (8, 9) are the valid index pairs where consecutive elements are equal.Input: arr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} Output: 0 No two consecutive elements in the given array are equal.  
 
Approach: Initialize count = 0 and traverse the array from arr[0] to arr[n – 2]. If the current element is equal to the next element in the array then increment the count. Print the count in the end.Below is the implementation of the above approach:  
C++
Java
Python3
C#
PHP
Javascript
// C++ implementation of the approach#include <iostream>using namespace std; // Function to return the count of consecutive// elements in the array which are equalint countCon(int ar[], int n){    int cnt = 0;     for (int i = 0; i < n - 1; i++) {         // If consecutive elements are same        if (ar[i] == ar[i + 1])            cnt++;    }    return cnt;} // Driver codeint main(){    int ar[] = { 1, 2, 2, 3, 4, 4, 5, 5, 5, 5 };    int n = sizeof(ar) / sizeof(ar[0]);    cout << countCon(ar, n);     return 0;}
// Java implementation of the approachpublic class GfG{     // Function to return the count of consecutive    // elements in the array which are equal    static int countCon(int ar[], int n)    {        int cnt = 0;             for (int i = 0; i < n - 1; i++)        {                 // If consecutive elements are same            if (ar[i] == ar[i + 1])                cnt++;        }        return cnt;    }         // Driver Code    public static void main(String []args){                 int ar[] = { 1, 2, 2, 3, 4, 4, 5, 5, 5, 5 };        int n = ar.length;        System.out.println(countCon(ar, n));    }} // This code is contributed by Rituraj Jain
# Python3 implementation of the approach # Function to return the count of consecutive# elements in the array which are equaldef countCon(ar, n):    cnt = 0     for i in range(n - 1):         # If consecutive elements are same        if (ar[i] == ar[i + 1]):            cnt += 1         return cnt # Driver codear = [1, 2, 2, 3, 4,      4, 5, 5, 5, 5]n = len(ar)print(countCon(ar, n)) # This code is contributed by mohit kumar
// C# implementation of the approachusing System; class GfG{     // Function to return the count of consecutive    // elements in the array which are equal    static int countCon(int[] ar, int n)    {        int cnt = 0;             for (int i = 0; i < n - 1; i++)        {                 // If consecutive elements are same            if (ar[i] == ar[i + 1])                cnt++;        }        return cnt;    }         // Driver Code    public static void Main()    {                 int[] ar = { 1, 2, 2, 3, 4, 4, 5, 5, 5, 5 };        int n = ar.Length;        Console.WriteLine(countCon(ar, n));    }} // This code is contributed by Code_Mech.
<?php// PHP implementation of the approach // Function to return the count of consecutive// elements in the array which are equalfunction countCon($ar, $n){    $cnt = 0;     for ($i = 0; $i < $n - 1; $i++)    {         // If consecutive elements are same        if ($ar[$i] == $ar[$i + 1])            $cnt++;    }    return $cnt;} // Driver code$ar = array(1, 2, 2, 3, 4, 4, 5, 5, 5, 5);$n = sizeof($ar);echo countCon($ar, $n); // This code is contributed// by Akanksha Rai?>
<script>// Javascript implementation of the approach     // Function to return the count of consecutive    // elements in the array which are equal    function countCon(ar,n)    {        let cnt = 0;               for (let i = 0; i < n - 1; i++)        {                   // If consecutive elements are same            if (ar[i] == ar[i + 1])                cnt++;        }        return cnt;    }         // Driver Code    let ar = [1, 2, 2, 3, 4, 4, 5, 5, 5, 5 ];    let n = ar.length;    document.write(countCon(ar, n)); // This code is contributed by unknown2108</script>
5
 
mohit kumar 29
rituraj_jain
Akanksha_Rai
Code_Mech
unknown2108
Constructive Algorithms
Arrays
Mathematical
Arrays
Mathematical
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