Print matrix in zig-zag fashion

26 May, 2022
Given a matrix of 2D array of n rows and m columns. Print this matrix in ZIG-ZAG fashion as shown in figure.  
Example:  
Input: 
1 2 3
4 5 6
7 8 9
Output: 
1 2 4 7 5 3 6 8 9
 
Approach of C++ code The approach is simple. Just simply iterate over every diagonal elements one at a time and change the direction according to the previous match. Approach of Python3 code This approach is simple. While travelling the matrix in the usual fashion, on basis of parity of the sum of the indices of the element, add that particular element to the list either at the beginning or at the end if sum of i and j is either even or odd respectively. Print the solution list as it is. 
C++
Java
Python3
C#
PHP
Javascript
/* C++ Program to print matrix in Zig-zag pattern*/#include <iostream>using namespace std;#define C 3 // Utility function to print matrix// in zig-zag formvoid zigZagMatrix(int arr[][C], int n, int m){    int row = 0, col = 0;     // Boolean variable that will true if we    // need to increment 'row' value otherwise    // false- if increment 'col' value    bool row_inc = 0;     // Print matrix of lower half zig-zag pattern    int mn = min(m, n);    for (int len = 1; len <= mn; ++len) {        for (int i = 0; i < len; ++i) {            cout << arr[row][col] << " ";             if (i + 1 == len)                break;            // If row_increment value is true            // increment row and decrement col            // else decrement row and increment            // col            if (row_inc)                ++row, --col;            else                --row, ++col;        }         if (len == mn)            break;         // Update row or col value according        // to the last increment        if (row_inc)            ++row, row_inc = false;        else            ++col, row_inc = true;    }     // Update the indexes of row and col variable    if (row == 0) {        if (col == m - 1)            ++row;        else            ++col;        row_inc = 1;    }    else {        if (row == n - 1)            ++col;        else            ++row;        row_inc = 0;    }     // Print the next half zig-zag pattern    int MAX = max(m, n) - 1;    for (int len, diag = MAX; diag > 0; --diag) {         if (diag > mn)            len = mn;        else            len = diag;         for (int i = 0; i < len; ++i) {            cout << arr[row][col] << " ";             if (i + 1 == len)                break;             // Update row or col value according            // to the last increment            if (row_inc)                ++row, --col;            else                ++col, --row;        }         // Update the indexes of row and col variable        if (row == 0 || col == m - 1) {            if (col == m - 1)                ++row;            else                ++col;             row_inc = true;        }         else if (col == 0 || row == n - 1) {            if (row == n - 1)                ++col;            else                ++row;             row_inc = false;        }    }} // Driver codeint main(){    int matrix[][3] = { { 1, 2, 3 },                        { 4, 5, 6 },                        { 7, 8, 9 } };    zigZagMatrix(matrix, 3, 3);     return 0;}
/* Java Program to print matrix in Zig-zag pattern*/class GFG {  static final int C = 3;   // Utility function to print matrix  // in zig-zag form  static void zigZagMatrix(int arr[][], int n, int m) {    int row = 0, col = 0;     // Boolean variable that will true if we    // need to increment 'row' value otherwise    // false- if increment 'col' value    boolean row_inc = false;     // Print matrix of lower half zig-zag pattern    int mn = Math.min(m, n);    for (int len = 1; len <= mn; ++len) {      for (int i = 0; i < len; ++i) {        System.out.print(arr[row][col] + " ");         if (i + 1 == len)          break;        // If row_increment value is true        // increment row and decrement col        // else decrement row and increment        // col        if (row_inc) {          ++row;          --col;        } else {          --row;          ++col;        }      }       if (len == mn)        break;       // Update row or col value according      // to the last increment      if (row_inc) {        ++row;        row_inc = false;      } else {        ++col;        row_inc = true;      }    }     // Update the indexes of row and col variable    if (row == 0) {      if (col == m - 1)        ++row;      else        ++col;      row_inc = true;    } else {      if (row == n - 1)        ++col;      else        ++row;      row_inc = false;    }     // Print the next half zig-zag pattern    int MAX = Math.max(m, n) - 1;    for (int len, diag = MAX; diag > 0; --diag) {       if (diag > mn)        len = mn;      else        len = diag;       for (int i = 0; i < len; ++i) {        System.out.print(arr[row][col] + " ");         if (i + 1 == len)          break;         // Update row or col value according        // to the last increment        if (row_inc) {          ++row;          --col;        } else {          ++col;          --row;        }      }       // Update the indexes of row and col variable      if (row == 0 || col == m - 1) {        if (col == m - 1)          ++row;        else          ++col;         row_inc = true;      }       else if (col == 0 || row == n - 1) {        if (row == n - 1)          ++col;        else          ++row;         row_inc = false;      }    }  }  // Driver code  public static void main(String[] args) {    int matrix[][] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};    zigZagMatrix(matrix, 3, 3);  }}// This code is contributed by Anant Agarwal.
# Program to print matrix in Zig-zag pattern matrix =[            [ 1, 2, 3,],            [ 4, 5, 6 ],            [ 7, 8, 9 ],        ]rows=3columns=3   solution=[[] for i in range(rows+columns-1)] for i in range(rows):    for j in range(columns):        sum=i+j        if(sum%2 ==0):             #add at beginning            solution[sum].insert(0,matrix[i][j])        else:             #add at end of the list            solution[sum].append(matrix[i][j])                      # print the solution as it asfor i in solution:    for j in i:        print(j,end=" ")                
// C# Program to print matrix// in Zig-zag patternusing System; class GFG {    static int C = 3;     // Utility function to print    // matrix in zig-zag form    static void zigZagMatrix(int[, ] arr, int n, int m)    {        int row = 0, col = 0;         // Boolean variable that will        // true if we need to increment        // 'row' valueotherwise false-        // if increment 'col' value        bool row_inc = false;         // Print matrix of lower half        // zig-zag pattern        int mn = Math.Min(m, n);        for (int len = 1; len <= mn; ++len) {                for (int i = 0; i < len; ++i) {                 Console.Write(arr[row, col] + " ");                 if (i + 1 == len)                    break;                 // If row_increment value is true                // increment row and decrement col                // else decrement row and increment                // col                if (row_inc) {                    ++row;                    --col;                }                else {                    --row;                    ++col;                }            }             if (len == mn)                break;             // Update row or col value            // according to the last            // increment            if (row_inc) {                    ++row;                    row_inc = false;            }            else {                ++col;                row_inc = true;            }        }         // Update the indexes of row        // and col variable        if (row == 0) {            if (col == m - 1)                ++row;            else                ++col;            row_inc = true;        }        else {            if (row == n - 1)                ++col;            else                ++row;            row_inc = false;        }         // Print the next half        // zig-zag pattern        int MAX = Math.Max(m, n) - 1;        for (int len, diag = MAX; diag > 0; --diag) {             if (diag > mn)                    len = mn;            else                len = diag;             for (int i = 0; i < len; ++i) {                    Console.Write(arr[row, col] + " ");                 if (i + 1 == len)                    break;                 // Update row or col value                // according to the last                // increment                if (row_inc) {                        ++row;                        --col;                }                else {                    ++col;                    --row;                }            }             // Update the indexes of            // row and col variable            if (row == 0 || col == m - 1) {                if (col == m - 1)                    ++row;                else                    ++col;                 row_inc = true;            }             else if (col == 0 || row == n - 1) {                if (row == n - 1)                    ++col;                else                    ++row;                 row_inc = false;            }        }    }     // Driver code    public static void Main()    {        int[, ] matrix = { { 1, 2, 3 },                        { 4, 5, 6 },                        { 7, 8, 9 } };        zigZagMatrix(matrix, 3, 3);    }} // This code is contributed by vt_m.
<?php// PHP Program to print// matrix in Zig-zag pattern$C = 3; // Utility function// to print matrix// in zig-zag formfunction zigZagMatrix($arr,                      $n, $m){    $row = 0; $col = 0;     // Boolean variable that    // will true if we need    // to increment 'row'    // value otherwise false-    // if increment 'col' value    $row_inc = false;     // Print matrix of lower    // half zig-zag pattern    $mn = min($m, $n);    for ($len = 1;         $len <= $mn; $len++)    {        for ($i = 0;             $i < $len; $i++)        {            echo ($arr[$row][$col]." ");             if ($i + 1 == $len)                break;                             // If row_increment value            // is true increment row            // and decrement col else            // decrement row and            // increment col            if ($row_inc)            {                $row++; $col--;            }            else            {                $row--; $col++;            }        }         if ($len == $mn)            break;         // Update row or col        // value according        // to the last increment        if ($row_inc)        {            ++$row; $row_inc = false;        }        else        {            ++$col; $row_inc = true;        }    }     // Update the indexes of    // row and col variable    if ($row == 0)    {        if ($col == $m - 1)            ++$row;        else            ++$col;        $row_inc = 1;    }    else    {        if ($row == $n - 1)            ++$col;        else            ++$row;        $row_inc = 0;    }     // Print the next half    // zig-zag pattern    $MAX = max($m, $n) - 1;    for ($len, $diag = $MAX;         $diag > 0; --$diag)    {        if ($diag > $mn)            $len = $mn;        else            $len = $diag;         for ($i = 0;             $i < $len; ++$i)        {            echo($arr[$row][$col] . " ");             if ($i + 1 == $len)                break;             // Update row or col            // value according to            // the last increment            if ($row_inc)            {                ++$row; --$col;            }            else            {                ++$col; --$row;            }        }         // Update the indexes of        // row and col variable        if ($row == 0 ||            $col == $m - 1)        {            if ($col == $m - 1)                ++$row;            else                ++$col;             $row_inc = true;        }         else if ($col == 0 ||                 $row == $n - 1)        {            if ($row == $n - 1)                ++$col;            else                ++$row;             $row_inc = false;        }    }} // Driver code$matrix = array(array(1, 2, 3),                array(4, 5, 6),                array(7, 8, 9));                 zigZagMatrix($matrix, 3, 3); // This code is contributed by// Manish Shaw(manishshaw1)?>
// Javascript Program to print matrix in Zig-zag patternvar n = 3, m = 3;var a = [[ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ]];var zigZagMatrix=function(arr, n, m){    var row = 0;    var col = 0;      // Variable that will be 1 if we    // need to increment 'row' value and 0 otherwise    // if we need to increment 'col' value    var row_inc = 0;      // print matrix of lower half zig-zag pattern    var mn = Math.min(m, n);    for (var len = 1; len <= mn; ++len) {        for (var i = 0; i < len; ++i) {            console.log(arr[row][col]);            console.log(" ");              if (i + 1 == len)                break;            // If row_increment value is true            // increment row and decrement col            // else decrement row and increment col            if (row_inc)                ++row, --col;            else                --row, ++col;        }          if (len == mn)            break;          // Update row or col value according        // to the last increment        if (row_inc)            ++row, row_inc = false;        else            ++col, row_inc = true;    }      // Update the indexes of row and col variable    if (row == 0) {        if (col == m - 1)            ++row;        else            ++col;        row_inc = 1;    }    else {        if (row == n - 1)            ++col;        else            ++row;        row_inc = 0;    }      // Print the next half zig-zag pattern    var MAX = Math.max(m, n) - 1;    for (var len, diag = MAX; diag > 0; --diag) {          if (diag > mn)            len = mn;        else            len = diag;          for (var i = 0; i < len; ++i) {            console.log(arr[row][col]);            console.log(" ");            if (i + 1 == len)                break;              // Update row or col value according            // to the last increment            if (row_inc)                ++row, --col;            else                ++col, --row;        }          // Update the indexes of row and col variable        if (row == 0 || col == m - 1) {            if (col == m - 1)                ++row;            else                ++col;              row_inc = true;        }          else if (col == 0 || row == n - 1) {            if (row == n - 1)                ++col;            else                ++row;            row_inc = false;        }    }}zigZagMatrix(a, 3, 3);  // This code is contributed by Sajal Aggarwal.
Output:  
1 2 4 7 5 3 6 8 9 
Time complexity: O(n*m) Auxiliary space: O(1) 
manishshaw1
nidhi_biet
19euit177
arorakashish0911
aggarwalsajal19
pattern-printing
Matrix
pattern-printing
Matrix
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Program to find largest element in an array
Matrix Chain Multiplication | DP-8
Rat in a Maze | Backtracking-2
Sudoku | Backtracking-7
Find the number of islands | Set 1 (Using DFS)
Rotate a matrix by 90 degree in clockwise direction without using any extra space
The Celebrity Problem
Unique paths in a Grid with Obstacles
Count all possible paths from top left to bottom right of a mXn matrix
Printing all solutions in N-Queen Problem