Given an array arr[] of length N, the task is to find the length of the longest subarray which consists of consecutive numbers in increasing order, from the array.
Examples:
Input: arr[] = {2, 3, 4, 6, 7, 8, 9, 10}
Output: 5
Explanation: Subarray {6, 7, 8, 9, 10} is the longest subarray satisfying the given conditions. Therefore, the required output is 5.Input: arr[] = {4, 5, 1, 2, 3, 4, 9, 10, 11, 12}
Output: 4
Naive Approach: The simplest approach to solve the problem is to traverse the array and for every index i, traverse from over-index and find the length of the longest subarray satisfying the given condition starting from i. Shift i to the index which does not satisfy the condition and check from that index. Finally, print the maximum length of such subarray obtained.
Below is the implementation of the above approach:Â
C++
// C++ implementation for the above approach #include <bits/stdc++.h> using namespace std; Â
// Function to find the longest subarray // with increasing contiguous elements int maxiConsecutiveSubarray( int arr[], int N) { Â
    // Stores the length of     // required longest subarray     int maxi = 0; Â
    for ( int i = 0; i < N - 1; i++) { Â
        // Stores the length of length of longest         // such subarray from ith index         int cnt = 1, j; Â
        for (j = i; j < N; j++) { Â
            // If consecutive elements are             // increasing and differ by 1             if (arr[j + 1] == arr[j] + 1) {                 cnt++;             } Â
            // Otherwise             else {                 break ;             }         } Â
        // Update the longest subarray         // obtained so far         maxi = max(maxi, cnt);         i = j;     } Â
    // Return the length obtained     return maxi; } Â
// Driver Code int main() { Â Â Â Â int N = 11; Â Â Â Â int arr[] = { 1, 3, 4, 2, 3, 4, Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 2, 3, 5, 6, 7 }; Â
    cout << maxiConsecutiveSubarray(arr, N);     return 0; } |
Java
// Java implementation for the above approach import java.util.*; Â
class GFG{      // Function to find the longest subarray // with increasing contiguous elements public static int maxiConsecutiveSubarray( int arr[],                                           int N) {          // Stores the length of     // required longest subarray     int maxi = 0 ; Â
    for ( int i = 0 ; i < N - 1 ; i++)     {                  // Stores the length of length of         // longest such subarray from ith         // index         int cnt = 1 , j; Â
        for (j = i; j < N - 1 ; j++)         {                          // If consecutive elements are             // increasing and differ by 1             if (arr[j + 1 ] == arr[j] + 1 )             {                 cnt++;             } Â
            // Otherwise             else             {                 break ;             }         } Â
        // Update the longest subarray         // obtained so far         maxi = Math.max(maxi, cnt);         i = j;     } Â
    // Return the length obtained     return maxi; } Â
// Driver Code public static void main(String args[]) { Â Â Â Â int N = 11 ; Â Â Â Â int arr[] = { 1 , 3 , 4 , 2 , 3 , 4 , Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 2 , 3 , 5 , 6 , 7 }; Â
    System.out.println(maxiConsecutiveSubarray(arr, N)); } } Â
// This code is contributed by hemanth gadarla |
Python3
# Python3 implementation for # the above approach Â
# Function to find the longest # subarray with increasing # contiguous elements def maxiConsecutiveSubarray(arr, N):        # Stores the length of     # required longest subarray     maxi = 0 ; Â
    for i in range (N - 1 ):         # Stores the length of         # length of longest such         # subarray from ith index         cnt = 1 ; Â
        for j in range (i, N - 1 ): Â
            # If consecutive elements are             # increasing and differ by 1             if (arr[j + 1 ] = = arr[j] + 1 ):                 cnt + = 1 ; Â
            # Otherwise             else :                 break ; Â
        # Update the longest subarray         # obtained so far         maxi = max (maxi, cnt);         i = j; Â
    # Return the length obtained     return maxi; Â
# Driver Code if __name__ = = '__main__' : Â Â Â Â Â Â Â N = 11 ; Â Â Â Â arr = [ 1 , 3 , 4 , 2 , 3 , Â Â Â Â Â Â Â Â Â Â Â 4 , 2 , 3 , 5 , 6 , 7 ]; Â
    print (maxiConsecutiveSubarray(arr, N)); Â
# This code is contributed by Rajput-Ji |
C#
// C# implementation for the // above approach using System; class GFG{      // Function to find the longest // subarray with increasing // contiguous elements public static int maxiConsecutiveSubarray( int []arr,                                           int N) {     // Stores the length of   // required longest subarray   int maxi = 0; Â
  for ( int i = 0; i < N - 1; i++)   {     // Stores the length of     // length of longest such     // subarray from ith index     int cnt = 1, j; Â
    for (j = i; j < N - 1; j++)     {       // If consecutive elements are       // increasing and differ by 1       if (arr[j + 1] == arr[j] + 1)       {         cnt++;       } Â
      // Otherwise       else       {         break ;       }     } Â
    // Update the longest subarray     // obtained so far     maxi = Math.Max(maxi, cnt);     i = j;   } Â
  // Return the length   // obtained   return maxi; } Â
// Driver Code public static void Main(String []args) { Â Â int N = 11; Â Â int []arr = {1, 3, 4, 2, 3, 4, Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 2, 3, 5, 6, 7}; Â Â Console.WriteLine( Â Â Â Â Â Â Â Â Â Â maxiConsecutiveSubarray(arr, N)); } } Â
// This code is contributed by 29AjayKumar |
Javascript
<script> // Javascript program to implement // the above approach Â
// Function to find the longest subarray // with increasing contiguous elements function maxiConsecutiveSubarray(arr, N) {           // Stores the length of     // required longest subarray     let maxi = 0;       for (let i = 0; i < N - 1; i++)     {                   // Stores the length of length of         // longest such subarray from ith         // index         let cnt = 1, j;           for (j = i; j < N - 1; j++)         {                           // If consecutive elements are             // increasing and differ by 1             if (arr[j + 1] == arr[j] + 1)             {                 cnt++;             }               // Otherwise             else             {                 break ;             }         }           // Update the longest subarray         // obtained so far         maxi = Math.max(maxi, cnt);         i = j;     }       // Return the length obtained     return maxi; } Â
    // Driver Code          let N = 11;     let arr = [ 1, 3, 4, 2, 3, 4,                   2, 3, 5, 6, 7 ];       document.write(maxiConsecutiveSubarray(arr, N));      </script> |
3
Time Complexity: O(N2)Â
Auxiliary Space: O(1)
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