Greatest contiguous sub-array of size K

Given an array arr[] of integers and an integer K, the task is to find the greatest contiguous sub-array of size K. Sub-array X is said to be greater than sub-array Y if the first non-matching element in both the sub-arrays has a greater value in X than in Y.

Examples:

Input: arr[] = {1, 4, 3, 2, 5}, K = 4
Output: 4 3 2 5
Two subarrays are {1, 4, 3, 2} and {4, 3, 2, 5}.
Hence, the greater one is {4, 3, 2, 5}

Input: arr[] = {1, 9, 2, 7, 9, 3}, K = 3
Output: 9 2 7

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: Generate all the sub-arrays of size K and store them in any Data-Structure. Sort all the sub-arrays, and the answer will be the last sub-array in the sorted Data-structure. In C++, we can use a vector of vectors to store sub-arrays of size K.

Below is the implementation of the above approach:

 // C++ implementation of the approach #include using namespace std;    // Function that returns the sub-array vector findSubarray(int a[], int k, int n) {        // Data-structure to store all     // the sub-arrays of size K     vector > vec;        // Iterate to find all the sub-arrays     for (int i = 0; i < n - k + 1; i++) {         vector temp;            // Store the sub-array elements in the array         for (int j = i; j < i + k; j++) {             temp.push_back(a[j]);         }            // Push the vector in the container         vec.push_back(temp);     }        // Sort the vector of elements     sort(vec.begin(), vec.end());        // The last sub-array in the sorted order     // will be the answer     return vec[vec.size() - 1]; }    // Driver code int main() {     int a[] = { 1, 4, 3, 2, 5 };     int k = 4;     int n = sizeof(a) / sizeof(a);        // Get the sub-array     vector ans = findSubarray(a, k, n);        for (auto it : ans)         cout << it << " "; }

 # Python3 implementation of the approach    # Function that returns the sub-array def findSubarray(a, k, n):        # Data-structure to store all     # the sub-arrays of size K     vec=[]        # Iterate to find all the sub-arrays     for i in range(n-k+1):         temp=[]            # Store the sub-array elements in the array         for j in range(i,i+k):             temp.append(a[j])            # Push the vector in the container         vec.append(temp)        # Sort the vector of elements     vec=sorted(vec)        # The last sub-array in the sorted order     # will be the answer     return vec[len(vec) - 1]    # Driver code    a =[ 1, 4, 3, 2, 5 ] k = 4 n = len(a)    # Get the sub-array ans = findSubarray(a, k, n)    for it in ans:     print(it,end=" ")        # This code is contributed by mohit kumar 29

Output:
4 3 2 5

Striver(underscore)79 at Codechef and codeforces D

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Improved By : mohit kumar 29

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