« back

Print Matrix in snake Pattern

Tags : matrix, geeksforgeeks, cpp, easy

Problem Statement - link #

Given a matrix of size N x N. Print the elements of the matrix in the snake like pattern depicted below.

Your Task: You dont need to read input or print anything. Complete the function snakePattern() that takes matrix as input parameter and returns a list of integers in order of the values visited in the snake pattern.

Expected Time Complexity: O(N*N)
Expected Auxiliary Space: O(N*N) for the resultant list only.

Examples #

Example 1:

Input:
N = 3 
matrix[][] = [[45, 48, 54], [21, 89, 87], [70, 78, 15]]
Output: 45 48 54 87 89 21 70 78 15 
Explanation:
Matrix is as below:
45 48 54
21 89 87
70 78 15
Printing it in snake pattern will lead to 
the output as 45 48 54 87 89 21 70 78 15.

Example 2:

Input:
N = 2
matrix[][] = [[1, 2], [3, 4]]
Output: 1 2 4 3
Explanation:
Matrix is as below:
1 2 
3 4
Printing it in snake pattern will 
give output as 1 2 4 3.

Constraints #

Solutions #

class Solution{
    public:
    //Function to return list of integers visited in snake pattern in matrix.
    vector<int> snakePattern(vector<vector<int> > matrix)
    {   
        // code here
        int m = matrix.size(), n = matrix[0].size();
        if( m==1 ) return matrix[0];
        vector<int> res;
        for( int i=0; i<m; i++){
            if(i%2==0)
                for(int j=0; j<n; j++)
                    res.push_back(matrix[i][j]);
            else
                for(int j=n-1; j>=0; j--)
                    res.push_back(matrix[i][j]);
        }
        return res;
    }

};