Algorithm JAVA

Java Programming – Length of the largest subarray with contiguous elements

An array of distinct integers, find length of the longest subarray which contains numbers that can be arranged in a continuous sequence.

Given an array of distinct integers, find length of the longest subarray which contains numbers that can be arranged in a continuous sequence.

Examples:

Input:  arr[] = {10, 12, 11};
Output: Length of the longest contiguous subarray is 3

Input:  arr[] = {14, 12, 11, 20};
Output: Length of the longest contiguous subarray is 2

Input:  arr[] = {1, 56, 58, 57, 90, 92, 94, 93, 91, 45};
Output: Length of the longest contiguous subarray is 5

The important thing to note in question is, it is given that all elements are distinct. If all elements are distinct, then a subarray has contiguous elements if and only if the difference between maximum and minimum elements in subarray is equal to the difference between last and first indexes of subarray. So the idea is to keep track of minimum and maximum element in every subarray.

The following is the implementation of above idea.

Java Program
class LargestSubArray2 
{
    // Utility functions to find minimum and maximum of
    // two elements
 
    int min(int x, int y) 
    {
        return (x < y) ? x : y;
    }
 
    int max(int x, int y) 
    {
        return (x > y) ? x : y;
    }
 
    // Returns length of the longest contiguous subarray
    int findLength(int arr[], int n) 
    {
        int max_len = 1;  // Initialize result
        for (int i = 0; i < n - 1; i++) 
        {
            // Initialize min and max for all subarrays starting with i
            int mn = arr[i], mx = arr[i];
 
            // Consider all subarrays starting with i and ending with j
            for (int j = i + 1; j < n; j++) 
            {
                // Update min and max in this subarray if needed
                mn = min(mn, arr[j]);
                mx = max(mx, arr[j]);
 
                // If current subarray has all contiguous elements
                if ((mx - mn) == j - i)
                    max_len = max(max_len, mx - mn + 1);
            }
        }
        return max_len;  // Return result
    }
 
    public static void main(String[] args) 
    {
        LargestSubArray2 large = new LargestSubArray2();
        int arr[] = {1, 56, 58, 57, 90, 92, 94, 93, 91, 45};
        int n = arr.length;
        System.out.println("Length of the longest contiguous subarray is "
                + large.findLength(arr, n));
    }
}

Output:

Length of the longest contiguous subarray is 5

Time Complexity of the above solution is O(n2).

READ  Java Programming - Largest Sum Contiguous Subarray

About the author

Wikitechy Editor

Wikitechy Editor

Wikitechy Founder, Author, International Speaker, and Job Consultant. My role as the CEO of Wikitechy, I help businesses build their next generation digital platforms and help with their product innovation and growth strategy. I'm a frequent speaker at tech conferences and events.

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