Min number of moves to traverse entire Matrix through connected cells with equal values
Given a matrix A[][] of dimension N*M, the task is to find the minimum number of moves required to traverse the entire matrix starting from (0, 0) by traversing connected cells with equal values at every step.
From a cell (i, j), cells (i + 1, j), (i – 1, j), (i, j – 1) and (i, j + 1) can be connected.
Examples:
Input: arr[][] = {{1, 1, 2, 2, 1}, {1, 1, 2, 2, 1}, {1, 1, 1, 3, 2}}
Output: 5
Explanation:
Minimum 5 moves are required to traverse the matrix.
First move: Starting from [0, 0], traverse cells [0, 1], [1, 1], [1, 0], [2, 0], [2, 1], [2, 2] as all these cells have the same value, 1.
Second move: Traverse cells [0, 2], [0, 3], [1, 3], [1, 2] as all these cells have value 2.
Third move: Traverse cells [0, 4], [1, 4] containing 1.
Fourth move: Traverse [2, 3] containing 3.
Fifth move: Traverse [2, 4] containing 4.Input: arr[][] = {{2, 1, 3}, {1, 1, 2}}
Output: 4
Explanation:
Minimum 4 moves are required to cover this 2-D array
First move: Traverse only [0, 0] as no other connected cell has value 2.
Second move: Traverse cells [0, 1], [1, 1], [1, 0] as these cells contain value 1.
Third move: Traverse cell [0, 2] containing 3.
Fourth move: Traverse cell [1, 2] containing 2.
Approach:
Follow the steps below to solve the problem:
- Create another matrix to fill each cell with distinct values.
- Traverse matrix A[][] starting from (0, 0). For every cell (i, j), check if its adjacent cells have the same value as A[i][j] or not.
- If any adjacent cell has the same value, replace that cell in B[][] with the value of B[i][j].
- The counting of remaining distinct elements in the B[][] matrix after completing the traversal of A[][], gives the required answer.
Below is the implementation of the above approach:
C++
// C++ program to find the // minimum number of moves // to traverse a given matrix #include <bits/stdc++.h> using namespace std; // Function to find the minimum // number of moves to traverse // the given matrix int solve( int A[][10], int N, int M) { int B[N][M]; int c = 1; set< int > s; // Constructing another matrix // consisting of distinct values for ( int i = 0; i < N; i++) { for ( int j = 0; j < M; j++) B[i][j] = c++; } // Updating the array B by checking // the values of A that if there are // same values connected // through an edge or not for ( int i = 0; i < N; i++) { for ( int j = 0; j < M; j++) { // Check for boundary // condition of the matrix if (i != 0) { // If adjacent cells have // same value if (A[i - 1][j] == A[i][j]) B[i - 1][j] = B[i][j]; } // Check for boundary // condition of the matrix if (i != N - 1) { // If adjacent cells have // same value if (A[i + 1][j] == A[i][j]) B[i + 1][j] = B[i][j]; } // Check for boundary // condition of the matrix if (j != 0) { // If adjacent cells have // same value if (A[i][j - 1] == A[i][j]) B[i][j - 1] = B[i][j]; } // Check for boundary // condition of the matrix if (j != M - 1) { // If adjacent cells have // same value if (A[i][j + 1] == A[i][j]) B[i][j + 1] = B[i][j]; } } } // Store all distinct elements // in a set for ( int i = 0; i < N; i++) { for ( int j = 0; j < M; j++) s.insert(B[i][j]); } // Return answer return s.size(); } // Driver Code int main() { int N = 2, M = 3; int A[][10] = { { 2, 1, 3 }, { 1, 1, 2 } }; // Function Call cout << solve(A, N, M); } |
Java
// Java program to find the // minimum number of moves // to traverse a given matrix import java.util.*; class GFG{ // Function to find the minimum // number of moves to traverse // the given matrix static int solve( int A[][], int N, int M) { int [][]B = new int [N][M]; int c = 1 ; HashSet<Integer> s = new HashSet<Integer>(); // Constructing another matrix // consisting of distinct values for ( int i = 0 ; i < N; i++) { for ( int j = 0 ; j < M; j++) B[i][j] = c++; } // Updating the array B by checking // the values of A that if there are // same values connected // through an edge or not for ( int i = 0 ; i < N; i++) { for ( int j = 0 ; j < M; j++) { // Check for boundary // condition of the matrix if (i != 0 ) { // If adjacent cells have // same value if (A[i - 1 ][j] == A[i][j]) B[i - 1 ][j] = B[i][j]; } // Check for boundary // condition of the matrix if (i != N - 1 ) { // If adjacent cells have // same value if (A[i + 1 ][j] == A[i][j]) B[i + 1 ][j] = B[i][j]; } // Check for boundary // condition of the matrix if (j != 0 ) { // If adjacent cells have // same value if (A[i][j - 1 ] == A[i][j]) B[i][j - 1 ] = B[i][j]; } // Check for boundary // condition of the matrix if (j != M - 1 ) { // If adjacent cells have // same value if (A[i][j + 1 ] == A[i][j]) B[i][j + 1 ] = B[i][j]; } } } // Store all distinct elements // in a set for ( int i = 0 ; i < N; i++) { for ( int j = 0 ; j < M; j++) s.add(B[i][j]); } // Return answer return s.size(); } // Driver Code public static void main(String[] args) { int N = 2 , M = 3 ; int A[][] = { { 2 , 1 , 3 }, { 1 , 1 , 2 } }; // Function Call System.out.print(solve(A, N, M)); } } // This code is contributed by 29AjayKumar |
Python3
# Python3 program to find the # minimum number of moves # to traverse a given matrix # Function to find the minimum # number of moves to traverse # the given matrix def solve(A, N, M): B = [] c = 1 s = set () # Constructing another matrix # consisting of distinct values for i in range (N): new = [] for j in range (M): new.append(c) c = c + 1 B.append(new) # Updating the array B by checking # the values of A that if there are # same values connected # through an edge or not for i in range (N): for j in range (M): # Check for boundary # condition of the matrix if i ! = 0 : # If adjacent cells have # same value if A[i - 1 ][j] = = A[i][j]: B[i - 1 ][j] = B[i][j] # Check for boundary # condition of the matrix if (i ! = N - 1 ): # If adjacent cells have # same value if A[i + 1 ][j] = = A[i][j]: B[i + 1 ][j] = B[i][j] # Check for boundary # condition of the matrix if (j ! = 0 ): # If adjacent cells have # same value if A[i][j - 1 ] = = A[i][j]: B[i][j - 1 ] = B[i][j] # Check for boundary # condition of the matrix if (j ! = M - 1 ): # If adjacent cells have # same value if (A[i][j + 1 ] = = A[i][j]): B[i][j + 1 ] = B[i][j] # Store all distinct elements # in a set for i in range (N): for j in range (M): s.add(B[i][j]) # Return answer return len (s) # Driver code N = 2 M = 3 A = [ [ 2 , 1 , 3 ], [ 1 , 1 , 2 ] ] # Function call print (solve(A, N, M)) # This code is contributed by divyeshrabadiya07 |
C#
// C# program to find the // minimum number of moves // to traverse a given matrix using System; using System.Collections.Generic; class GFG{ // Function to find the minimum // number of moves to traverse // the given matrix static int solve( int [,]A, int N, int M) { int [,]B = new int [N, M]; int c = 1; HashSet< int > s = new HashSet< int >(); // Constructing another matrix // consisting of distinct values for ( int i = 0; i < N; i++) { for ( int j = 0; j < M; j++) B[i, j] = c++; } // Updating the array B by checking // the values of A that if there are // same values connected // through an edge or not for ( int i = 0; i < N; i++) { for ( int j = 0; j < M; j++) { // Check for boundary // condition of the matrix if (i != 0) { // If adjacent cells have // same value if (A[i - 1, j] == A[i, j]) B[i - 1, j] = B[i, j]; } // Check for boundary // condition of the matrix if (i != N - 1) { // If adjacent cells have // same value if (A[i + 1, j] == A[i, j]) B[i + 1, j] = B[i, j]; } // Check for boundary // condition of the matrix if (j != 0) { // If adjacent cells have // same value if (A[i, j - 1] == A[i, j]) B[i, j - 1] = B[i, j]; } // Check for boundary // condition of the matrix if (j != M - 1) { // If adjacent cells have // same value if (A[i, j + 1] == A[i, j]) B[i, j + 1] = B[i, j]; } } } // Store all distinct elements // in a set for ( int i = 0; i < N; i++) { for ( int j = 0; j < M; j++) s.Add(B[i, j]); } // Return answer return s.Count; } // Driver Code public static void Main(String[] args) { int N = 2, M = 3; int [,]A = { { 2, 1, 3 }, { 1, 1, 2 } }; // Function Call Console.Write(solve(A, N, M)); } } // This code is contributed by 29AjayKumar |
Javascript
<script> // Javascript program to find the // minimum number of moves // to traverse a given matrix // Function to find the minimum // number of moves to traverse // the given matrix function solve(A, N, M) { var B = Array.from(Array(N), ()=> Array(M)); var c = 1; var s = new Set(); // Constructing another matrix // consisting of distinct values for ( var i = 0; i < N; i++) { for ( var j = 0; j < M; j++) B[i][j] = c++; } // Updating the array B by checking // the values of A that if there are // same values connected // through an edge or not for ( var i = 0; i < N; i++) { for ( var j = 0; j < M; j++) { // Check for boundary // condition of the matrix if (i != 0) { // If adjacent cells have // same value if (A[i - 1][j] == A[i][j]) B[i - 1][j] = B[i][j]; } // Check for boundary // condition of the matrix if (i != N - 1) { // If adjacent cells have // same value if (A[i + 1][j] == A[i][j]) B[i + 1][j] = B[i][j]; } // Check for boundary // condition of the matrix if (j != 0) { // If adjacent cells have // same value if (A[i][j - 1] == A[i][j]) B[i][j - 1] = B[i][j]; } // Check for boundary // condition of the matrix if (j != M - 1) { // If adjacent cells have // same value if (A[i][j + 1] == A[i][j]) B[i][j + 1] = B[i][j]; } } } // Store all distinct elements // in a set for ( var i = 0; i < N; i++) { for ( var j = 0; j < M; j++) s.add(B[i][j]); } // Return answer return s.size; } // Driver Code var N = 2, M = 3; var A = [ [ 2, 1, 3 ], [ 1, 1, 2 ]]; // Function Call document.write( solve(A, N, M)); </script> |
4
Time Complexity: O(N2)
Auxiliary Space: O(N2)
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