Longest subarray with all elements same

14 May, 2021
Given an array arr[] of size N, the task is to find the largest subarray which consists of all equal elements.Examples:  
Input: arr[] = {1, 1, 2, 2, 2, 3, 3}; Output: 3 Explanation: Longest subarray with equal elements is {2, 2, 2}Input: arr[] = {1, 1, 2, 2, 2, 3, 3, 3, 3}; Output: 4 Explanation: Longest subarray with equal elements is {3, 3, 3, 3}  
 
Approach: The idea is to traverse the array and check that the current element is equal to the previous element or not. If yes then increment the length of the longest subarray by 1. Otherwise, the current longest subarray is equal to 1. Also, update the longest subarray with equal elements at each step of the iteration.Below is the implementation of the above approach:  
C++
Java
Python3
C#
Javascript
// C++ program to find largest// subarray with all equal elements. #include <bits/stdc++.h>using namespace std; // Function to find largest sub// array with all equal elements.int subarray(int arr[], int n){     int ans = 1, temp = 1;     // Traverse the array    for (int i = 1; i < n; i++) {         // If element is same as        // previous increment temp value        if (arr[i] == arr[i - 1]) {            ++temp;        }        else {            ans = max(ans, temp);            temp = 1;        }    }    ans = max(ans, temp);     // Return the required answer    return ans;} // Driver codeint main(){    int arr[] = { 2, 2, 1, 1,                  2, 2, 2, 3, 3 };    int n = sizeof(arr) / sizeof(arr[0]);     // Function call    cout << subarray(arr, n);     return 0;}
// Java program to find largest// subarray with all equal elements.import java.util.*; class GFG{ // Function to find largest sub// array with all equal elements.static int subarray(int arr[], int n){    int ans = 1, temp = 1;     // Traverse the array    for(int i = 1; i < n; i++)    {                // If element is same as       // previous increment temp value       if (arr[i] == arr[i - 1])       {           ++temp;       }       else       {           ans = Math.max(ans, temp);           temp = 1;       }    }    ans = Math.max(ans, temp);     // Return the required answer    return ans;} // Driver codepublic static void main(String[] args){    int arr[] = { 2, 2, 1, 1, 2,                  2, 2, 3, 3 };    int n = arr.length;     // Function call    System.out.print(subarray(arr, n));}} // This code is contributed by AbhiThakur
# Python3 program to find largest# subarray with all equal elements. # Function to find largest sub# array with all equal elements.def subarray(arr, n):         ans, temp = 1, 1     # Traverse the array    for i in range(1, n):         # If element is same as previous        # increment temp value        if arr[i] == arr[i - 1]:            temp = temp + 1        else:            ans = max(ans, temp)            temp = 1                     ans = max(ans, temp)     # Return the required answer    return ans # Driver codearr = [ 2, 2, 1, 1, 2,        2, 2, 3, 3 ]n = len(arr) # Function callprint(subarray(arr, n)) # This code is contributed by jrishabh99
// C# program to find largest// subarray with all equal elements.using System;class GFG{ // Function to find largest sub// array with all equal elements.static int subarray(int[] arr, int n){    int ans = 1, temp = 1;     // Traverse the array    for(int i = 1; i < n; i++)    {                // If element is same as       // previous increment temp value       if (arr[i] == arr[i - 1])       {           ++temp;       }       else       {           ans = Math.Max(ans, temp);           temp = 1;       }    }    ans = Math.Max(ans, temp);         // Return the required answer    return ans;} // Driver codepublic static void Main(){    int[] arr = { 2, 2, 1, 1, 2,                  2, 2, 3, 3 };    int n = arr.Length;     // Function call    Console.Write(subarray(arr, n));}} // This code is contributed by Nidhi_biet
<script> // Javascript program to find largest// subarray with all equal elements. // Function to find largest sub// array with all equal elements.function subarray(arr, n){     var ans = 1, temp = 1;     // Traverse the array    for (var i = 1; i < n; i++) {         // If element is same as        // previous increment temp value        if (arr[i] == arr[i - 1]) {            ++temp;        }        else {            ans = Math.max(ans, temp);            temp = 1;        }    }    ans = Math.max(ans, temp);     // Return the required answer    return ans;} // Driver codevar arr = [ 2, 2, 1, 1,              2, 2, 2, 3, 3 ];var n = arr.length; // Function calldocument.write( subarray(arr, n)); </script>
3
 
Time Complexity: O(N) 
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