Skip to content
Related Articles
Open in App
Not now

Related Articles

Maximum neighbor element in a matrix within distance K

Improve Article
Save Article
  • Difficulty Level : Hard
  • Last Updated : 02 May, 2022
Improve Article
Save Article

Given a matrix mat[][] and an integer K, the task is to find the maximum neighbor within an absolute distance of K for each element of the matrix.
In other words for each Matrix[i][j] find maximum Matrix[p][q] such that abs (i-p) + abs (j-q) ≤ K.
Examples: 
 

Input: mat[][] = {{1, 2}, {4, 5}}, K = 1 
Output: {{4, 5}, {5, 5}} 
Explanation: 
Maximum neighbour to the element mat[0][0] = 4 (Distance = 1) 
Maximum neighbour to the element mat[0][1] = 5 (Distance = 1) 
Maximum neighbour to the element mat[1][0] = 5 (Distance = 1) 
Maximum neighbour to the element mat[1][1] = 5 (Distance = 0)
Input: mat[][] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}, K = 2 
Output: {{7, 8, 9}, {8, 9, 9}, {9, 9, 9}} 
 

 

Approach: The idea is to iterate over a loop from 1 to K, to choose the element from neighbors with distance less than or equal to K. Each time, Iterate over the matrix to find the maximum adjacent element for each element of the matrix. 
Below is the implementation of the above approach:
 

C++




// C++ implementation to find the
// maximum neighbor element within
// the distance of less than K
 
#include <bits/stdc++.h>
 
using namespace std;
 
// Function to print the matrix
void printMatrix(vector<vector<int> > A)
{
    // Loop to iterate over the matrix
    for (int i = 0; i < A.size(); i++) {
        for (int j = 0; j < A[0].size(); j++)
            cout << A[i][j] << ' ';
        cout << '\n';
    }
}
 
// Function to find the maximum
// neighbor within the distance
// of less than equal to K
vector<vector<int> > getMaxNeighbour(
        vector<vector<int> >& A, int K)
{
    vector<vector<int> > ans = A;
     
    // Loop to find the maximum
    // element within the distance
    // of less than K
    for (int q = 1; q <= K; q++) {
        for (int i = 0; i < A.size(); i++) {
            for (int j = 0; j < A[0].size(); j++) {
                int maxi = ans[i][j];
                if (i > 0)
                    maxi = max(
                        maxi, ans[i - 1][j]);
                if (j > 0)
                    maxi = max(
                        maxi, ans[i][j - 1]);
                if (i < A.size() - 1)
                    maxi = max(
                        maxi, ans[i + 1][j]);
                if (j < A[0].size() - 1)
                    maxi = max(
                        maxi, ans[i][j + 1]);
                A[i][j] = maxi;
            }
        }
        ans = A;
    }
    return ans;
}
 
// Driver Code
int main()
{
    vector<vector<int> > B = { { 1, 2, 3 },
                  { 4, 5, 6 }, { 7, 8, 9 } };
    printMatrix(getMaxNeighbour(B, 2));
    return 0;
}

Java




// Java implementation to find the
// maximum neighbor element within
// the distance of less than K
import java.util.*;
 
class GFG {
 
    // Function to print the matrix
    static void printMatrix(int[][] A)
    {
 
        // Loop to iterate over the matrix
        for (int i = 0; i < A.length; i++) {
            for (int j = 0; j < A[0].length; j++)
                System.out.print(A[i][j] + " ");
            System.out.print('\n');
        }
    }
 
    // Function to copy content of one matrix into another
    static void copyMatrix(int[][] A, int[][] B)
    {
        int row = B.length;
        int col = B[0].length;
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < col; j++) {
                A[i][j] = B[i][j];
            }
        }
    }
 
    // Function to find the maximum
    // neighbor within the distance
    // of less than equal to K
    static int[][] getMaxNeighbour(int[][] A, int K)
    {
        int[][] ans = new int[A.length][A[0].length];
        copyMatrix(ans, A);
 
        // Loop to find the maximum
        // element within the distance
        // of less than K
        for (int q = 1; q <= K; q++) {
            for (int i = 0; i < A.length; i++) {
                for (int j = 0; j < A[0].length; j++) {
                    int maxi = ans[i][j];
                    if (i > 0)
                        maxi
                            = Math.max(maxi, ans[i - 1][j]);
                    if (j > 0)
                        maxi
                            = Math.max(maxi, ans[i][j - 1]);
                    if (i < A.length - 1)
                        maxi
                            = Math.max(maxi, ans[i + 1][j]);
                    if (j < A[0].length - 1)
                        maxi
                            = Math.max(maxi, ans[i][j + 1]);
                    A[i][j] = maxi;
                }
            }
            copyMatrix(ans, A);
        }
        return ans;
    }
 
    // Driver Code
    public static void main(String[] args)
    {
        int[][] B
            = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };
 
        printMatrix(getMaxNeighbour(B, 2));
    }
}
 
// This code is contributed by Princi Singh

Python3




# Python3 implementation to find the
# maximum neighbor element within
# the distance of less than K
  
# Function to print the matrix
def printMatrix(A):
 
    # Loop to iterate over the matrix
    for i in range(len(A)):
        for j in range(len(A[0])):
            print(A[i][j], end = ' ')
        print()
          
# Function to find the maximum
# neighbor within the distance
# of less than equal to K
def getMaxNeighbour( A, K ):
 
    ans = A;
      
    # Loop to find the maximum
    # element within the distance
    # of less than K
    for q in range(1, K + 1):
        for i in range(len(A)):
            for j in range(len(A[0])):
                 
                maxi = ans[i][j];
                 
                if (i > 0):
                    maxi = max(maxi, ans[i - 1][j]);
                if (j > 0):
                    maxi = max(maxi, ans[i][j - 1]);
                     
                if (i < len(A) - 1):
                    maxi = max(maxi, ans[i + 1][j]);
                     
                if (j < len(A[0]) - 1):
                    maxi = max(maxi, ans[i][j + 1]);
                     
                A[i][j] = maxi;
 
        ans = A;
     
    return ans;
  
# Driver Code
if __name__=='__main__':
 
    B = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ]
    printMatrix(getMaxNeighbour(B, 2));
     
# This code is contributed by ruttvik_56

C#




// C# implementation to find the
// maximum neighbor element within
// the distance of less than K
using System;
 
class GFG{
 
// Function to print the matrix
static void printMatrix(int [,] A)
{
     
    // Loop to iterate over the matrix
    for(int i = 0; i < A.GetLength(0); i++)
    {
       for(int j = 0; j < A.GetLength(1); j++)
          Console.Write(A[i, j] + " ");
       Console.Write('\n');
    }
}
 
// Function to find the maximum
// neighbor within the distance
// of less than equal to K
static int [,] getMaxNeighbour(int [,] A,
                               int K)
{
    int [,] ans = A;
     
    // Loop to find the maximum
    // element within the distance
    // of less than K
    for(int q = 1; q <= K; q++)
    {
       for(int i = 0; i < A.GetLength(0); i++)
       {
          for(int j = 0; j < A.GetLength(1); j++)
          {
             int maxi = ans[i, j];
             if (i > 0)
                 maxi = Math.Max(maxi,
                                 ans[i - 1, j]);
             if (j > 0)
                 maxi = Math.Max(maxi,
                                 ans[i, j - 1]);
             if (i < A.GetLength(0) - 1)
                 maxi = Math.Max(maxi,
                                 ans[i + 1, j]);
             if (j < A.GetLength(0) - 1)
                 maxi = Math.Max(maxi,
                                 ans[i, j + 1]);
             A[i, j] = maxi;
          }
       }
       ans = A;
    }
    return ans;
}
 
// Driver Code
public static void Main(String[] args)
{
    int [,] B = { { 1, 2, 3 },
                  { 4, 5, 6 },
                  { 7, 8, 9 } };
                     
    printMatrix(getMaxNeighbour(B, 2));
}
}
 
// This code is contributed by Princi Singh

Javascript




<script>
 
// JavaScript implementation to find the
// maximum neighbor element within
// the distance of less than K
 
// Function to print the matrix
function printMatrix(A)
{
    // Loop to iterate over the matrix
    for (let i = 0; i < A.length; i++) {
        for (let j = 0; j < A[0].length; j++)
            document.write(A[i][j],' ');
        document.write('</br>');
    }
}
 
// Function to find the maximum
// neighbor within the distance
// of less than equal to K
function getMaxNeighbour(A,K)
{
    let ans = A;
     
    // Loop to find the maximum
    // element within the distance
    // of less than K
    for (let q = 1; q <= K; q++) {
        for (let i = 0; i < A.length; i++) {
            for (let j = 0; j < A[0].length; j++) {
                let maxi = ans[i][j];
                if (i > 0)
                    maxi = Math.max(
                        maxi, ans[i - 1][j]);
                if (j > 0)
                    maxi = Math.max(
                        maxi, ans[i][j - 1]);
                if (i < A.length - 1)
                    maxi = Math.max(
                        maxi, ans[i + 1][j]);
                if (j < A[0].length - 1)
                    maxi = Math.max(
                        maxi, ans[i][j + 1]);
                A[i][j] = maxi;
            }
        }
        ans = A;
    }
    return ans;
}
 
// Driver Code
 
let B = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ];
printMatrix(getMaxNeighbour(B, 2));
 
// This code is contributed by shinjanpatra.
<script>

Output: 

7 8 9 
8 9 9 
9 9 9

 

Time Complexity: O(M*N*K) 
Space Complexity: O(M*N)
 


My Personal Notes arrow_drop_up
Related Articles

Start Your Coding Journey Now!