import java.util.*;
class GfG {
    static void print(int [][] mat) {
        // すべての行を走査
        for (int i = 0; i < mat.length; i++) {
            // 現在の行が偶数かどうか
            if (i % 2 == 0) {
                // 左から右へ印刷
                for (int j = 0; j < mat[0].length; j++)
                    System.out.print(mat[i][j] + " ");
            }
            // 現在の行が奇数かどうか
            else {
                // 右から左へ印刷
                for (int j = mat[0].length - 1; j >= 0; j--)
                    System.out.print(mat[i][j] + " ");
            }
        }
    }
    public static void main(String[] args) {
        int mat[][] = new int [][] { { 10, 20, 30, 40 },
                                     { 15, 25, 35, 45 },
                                     { 27, 29, 37, 48 },
                                     { 32, 33, 39, 50 } };
        print(mat);
    }
}

# Python 3 program to print
# matrix in snake order
M = 4
N = 4
def printf(mat):
    global M, N
    # Traverse through all rows
    for i in range(M):
        # If current row is
        # even, print from
        # left to right
        if i % 2 == 0:
            for j in range(N):
                print(str(mat[i][j]),
                                    end = " ")
        # If current row is
        # odd, print from
        # right to left
        else:
            for j in range(N - 1, - 1, - 1):
                print(str(mat[i][j]),
                                    end = " ")

# Driver code
mat = [[10, 20, 30, 40],
          [15, 25, 35, 45],
          [27, 29, 37, 48],
          [32, 33, 39, 50]]
printf(mat)