Magic Square of Odd Order
Last Updated : 04 May, 2025
Given a positive integer n, your task is to generate a magic square of order n * n. A magic square of order n is an n * n grid filled with the numbers 1 through n² so that every row, every column, and both main diagonals each add up to the same total, called the magic constant (or magic sum) M. Because it uses each integer from 1 to n² exactly once, the value of M depends only on n, and has the value
M = n (n ^ 2 + 1) / 2
How does this formula work?
Sum of all numbers is 1 + 2 + 3, ... n^2 which is equal to n^2 * (n^2 + 1)/2 [We have simply applied natural number sum formula for n = n^2]. Now a magic square contains n divisions of sum M, so we can write n x M = n^2 * (n^2 + 1)/2. From this expression, we can derive, M = n * (n^2 + 1)/2
For the first few “normal” magic squares (i.e. using 1…n²), the magic constants are:
Order (n) | Magic Constant (M) |
---|
3 | 3(3^2 + 1) / 2 = 15 |
4 | 4(4^2 + 1) / 2 = 34 |
5 | 5(5^2 + 1) / 2 = 65 |
6 | 6(6^2 + 1) / 2 = 111 |
Examples:
Input: n = 3
Output: [ [2, 7, 6],
[9, 5, 1],
[4, 3, 8] ]
Explanation: Sum in each row, each column and both main diagonal is equal (15) and the matrix contains unique values from 1 to 9.
Input: n = 5
Output: [ [9, 3, 22, 16, 15],
[2, 21, 20, 14, 8],
[25, 19, 13, 7, 1],
[18, 12, 6, 5, 24],
[11, 10, 4, 23, 17] ]
Explanation: Sum in each row, each column and both main diagonal is equal (65) and the matrix contains unique values from 1 to 25.
Note: The below given approaches work only for odd value of n.
[Expected Approach - 1] - O(n ^ 2) Time and O(n ^ 2) Space
Let us take a look at first few magic squares to find a pattern for filling numbers.
Magic Square of size 3
2 7 6
9 5 1
4 3 8
Magic Square of size 5
9 3 22 16 15
2 21 20 14 8
25 19 13 7 1
18 12 6 5 24
11 10 4 23 17]
Magic Square of size 7
20 12 4 45 37 29 28
11 3 44 36 35 27 19
2 43 42 34 26 18 10
49 41 33 25 17 9 1
40 32 24 16 8 7 48
31 23 15 14 6 47 39
22 21 13 5 46 38 30
Did you find any pattern in which the numbers are stored?
- In any magic square, the first number i.e. 1 is stored at position (n/2, n-1). Let this position be (i, j). The next number is stored at position (i-1, j+1) where we can consider each row & column as circular array i.e. they wrap around.
- At any time, if the calculated row position becomes -1, it will wrap around to n-1. Similarly, if the calculated column position becomes n, it will wrap around to 0.
- If the magic square already contains a number at the calculated position, calculated column position will be decremented by 2, and calculated row position will be incremented by 1.
- If the calculated row position is -1 & calculated column position is n, the new position would be: (0, n-2).
The idea is to place each integer from 1 up to n² one at a time, always moving up one row and right one column from the last placement—wrapping around the edges as if rows and columns were circular—and applying two special corrections when that move lands outside the square on both axes or on an already‑filled cell.
Follow the below given steps:
- Create an n × n grid
mat
initialized to zeros, and set your starting position to row i = n/2
, column j = n − 1
. - Repeat for each
num
from 1 through n²:- Compute the candidate position by decrementing
i
by 1 and incrementing j
by 1. - If that move sends you both above the top (i < 0) and beyond the right edge (j == n), reset to
i = 0
, j = n − 2
. - Otherwise, if only one coordinate is out of range, wrap it around: any
i < 0
becomes n − 1
, any j == n
becomes 0. - If
mat[i][j]
is already nonzero, backtrack two columns (subtract 2 from j
) and move down one row (add 1 to i
), and retry placing the same num
. - Otherwise, store
num
in mat[i][j]
, then proceed to the next number by again decrementing i
and incrementing j
.
- Once all numbers are placed without conflict,
mat
is your completed magic square.
C++ #include <bits/stdc++.h> using namespace std; // A function to generate odd sized magic squares vector<vector<int>> generateSquare(int n) { // initialize magic square vector<vector<int>> mat(n, vector<int>(n, 0)); // Initialize position for 1 int i = n / 2; int j = n - 1; // One by one put all values in magic square for (int num = 1; num <= n * n;) { // if row is -1 and column becomes n, // set row = 0, col = n -2 if (i == -1 && j == n) { j = n - 2; i = 0; } else { // If next number goes to out of // square's right side if (j == n) j = 0; // If next number goes to out of // square's upper side if (i < 0) i = n - 1; } // If number is already present decrement // column by 2, and increment row by 1 if (mat[i][j]) { j -= 2; i++; continue; } else { // set number mat[i][j] = num++; } // increment and decrement // column and row by 1 respectively j++; i--; } return mat; } int main() { int n = 5; vector<vector<int>> magicSquare = generateSquare(n); for(int i = 0; i < n; i++) { for(int j = 0; j < n; j++) { cout << magicSquare[i][j] << " "; } cout << endl; } return 0; }
Java // A function to generate odd sized magic squares import java.util.Arrays; public class MagicSquare { public static int[][] generateSquare(int n) { // initialize magic square int[][] mat = new int[n][n]; // Initialize position for 1 int i = n / 2; int j = n - 1; // One by one put all values in magic square for (int num = 1; num <= n * n;) { // if row is -1 and column becomes n, // set row = 0, col = n -2 if (i == -1 && j == n) { j = n - 2; i = 0; } else { // If next number goes to out of // square's right side if (j == n) j = 0; // If next number goes to out of // square's upper side if (i < 0) i = n - 1; } // If number is already present decrement // column by 2, and increment row by 1 if (mat[i][j] != 0) { j -= 2; i++; continue; } else { // set number mat[i][j] = num++; } // increment and decrement // column and row by 1 respectively j++; i--; } return mat; } public static void main(String[] args) { int n = 5; int[][] magicSquare = generateSquare(n); for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { System.out.print(magicSquare[i][j] + " "); } System.out.println(); } } }
Python # A function to generate odd sized magic squares def generate_square(n): # initialize magic square mat = [[0] * n for _ in range(n)] # Initialize position for 1 i = n // 2 j = n - 1 # One by one put all values in magic square for num in range(1, n * n + 1): # if row is -1 and column becomes n, # set row = 0, col = n -2 if i == -1 and j == n: j = n - 2 i = 0 else: # If next number goes to out of # square's right side if j == n: j = 0 # If next number goes to out of # square's upper side if i < 0: i = n - 1 # If number is already present decrement # column by 2, and increment row by 1 if mat[i][j]: j -= 2 i += 1 continue else: # set number mat[i][j] = num # increment and decrement # column and row by 1 respectively j += 1 i -= 1 return mat n = 5 magic_square = generate_square(n) for row in magic_square: print(" ".join(map(str, row)))
C# // A function to generate odd sized magic squares using System; using System.Linq; class MagicSquare { public static int[,] GenerateSquare(int n) { // initialize magic square int[,] mat = new int[n, n]; // Initialize position for 1 int i = n / 2; int j = n - 1; // One by one put all values in magic square for (int num = 1; num <= n * n;) { // if row is -1 and column becomes n, // set row = 0, col = n -2 if (i == -1 && j == n) { j = n - 2; i = 0; } else { // If next number goes to out of // square's right side if (j == n) j = 0; // If next number goes to out of // square's upper side if (i < 0) i = n - 1; } // If number is already present decrement // column by 2, and increment row by 1 if (mat[i, j] != 0) { j -= 2; i++; continue; } else { // set number mat[i, j] = num++; } // increment and decrement // column and row by 1 respectively j++; i--; } return mat; } public static void Main() { int n = 5; int[,] magicSquare = GenerateSquare(n); for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { Console.Write(magicSquare[i, j] + " "); } Console.WriteLine(); } } }
JavaScript // A function to generate odd sized magic squares function generateSquare(n) { // initialize magic square let mat = Array.from({ length: n }, () => Array(n).fill(0)); // Initialize position for 1 let i = Math.floor(n / 2); let j = n - 1; // One by one put all values in magic square for (let num = 1; num <= n * n;) { // if row is -1 and column becomes n, // set row = 0, col = n -2 if (i === -1 && j === n) { j = n - 2; i = 0; } else { // If next number goes to out of // square's right side if (j === n) j = 0; // If next number goes to out of // square's upper side if (i < 0) i = n - 1; } // If number is already present decrement // column by 2, and increment row by 1 if (mat[i][j]) { j -= 2; i++; continue; } else { // set number mat[i][j] = num++; } // increment and decrement // column and row by 1 respectively j++; i--; } return mat; } let n = 5; let magicSquare = generateSquare(n); for (let i = 0; i < n; i++) { console.log(magicSquare[i].join(' ')); }
Output9 3 22 16 15 2 21 20 14 8 25 19 13 7 1 18 12 6 5 24 11 10 4 23 17
[Expected Approach - 2] - Using Modulo Arithmetic - O(n ^ 2) Time and O(n ^ 2) Space
The idea is to treat he grid as if its rows and columns wrap around (using modulo arithmetic), placing each integer in sequence by moving one step up and one step right—except whenever you’ve just placed a multiple of n, you instead move one step left. This simple cyclic movement ensures every row, column, and diagonal sums to the same magic constant.
Follow the below given steps:
- Create an empty n×n grid
mat
and set your starting coordinates to row i = n/2
and column j = n – 1
. - Place the first number (1) at
(i, j)
. - For each next
num
from 2 up to n²:- If the previous number was a multiple of n, move one column left; otherwise, move one row up and one column right.
- After adjusting
i
or j
, add n
and then take each coordinate modulo n to wrap around the grid. - Place
num
at the resulting (i, j)
.
- Continue until all numbers 1 through n² have been placed; the wrapping guarantees the magic‑square property.
Below is given the implementation:
C++ #include <bits/stdc++.h> using namespace std; // A function to generate odd sized magic squares vector<vector<int>> generateSquare(int n) { // initialize magic square vector<vector<int>> mat(n, vector<int>(n, 0)); // Initialize position for 1 int i = n / 2; int j = n - 1; // One by one put all values in magic square for (int num = 1; num <= n * n; num++) { // put the current element at (i, j) mat[i][j] = num; // if we get multiple of n, move left if(num % n == 0) { j--; } // else move to top-right else { i--; j++; } // add n and take modulo // to avoid out of bounds i += n; i %= n; j += n; j %= n; } return mat; } int main() { int n = 5; vector<vector<int>> magicSquare = generateSquare(n); for(int i = 0; i < n; i++) { for(int j = 0; j < n; j++) { cout << magicSquare[i][j] << " "; } cout << endl; } return 0; }
Java import java.util.*; class GfG { // A function to generate odd sized magic squares static List<List<Integer>> generateSquare(int n) { // initialize magic square List<List<Integer>> mat = new ArrayList<>(); for (int ii = 0; ii < n; ii++) { mat.add(new ArrayList<>(Collections.nCopies(n, 0))); } // Initialize position for 1 int i = n / 2; int j = n - 1; // One by one put all values in magic square for (int num = 1; num <= n * n; num++) { // put the current element at (i, j) mat.get(i).set(j, num); // if we get multiple of n, move left if (num % n == 0) { j--; } // else move to top-right else { i--; j++; } // add n and take modulo // to avoid out of bounds i += n; i %= n; j += n; j %= n; } return mat; } public static void main(String[] args) { int n = 5; List<List<Integer>> magicSquare = generateSquare(n); for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { System.out.print(magicSquare.get(i).get(j) + " "); } System.out.println(); } } }
Python # A function to generate odd sized magic squares def generateSquare(n): # initialize magic square mat = [[0 for _ in range(n)] for _ in range(n)] # Initialize position for 1 i = n // 2 j = n - 1 # One by one put all values in magic square for num in range(1, n * n + 1): # put the current element at (i, j) mat[i][j] = num # if we get multiple of n, move left if num % n == 0: j -= 1 # else move to top-right else: i -= 1 j += 1 # add n and take modulo # to avoid out of bounds i = (i + n) % n j = (j + n) % n return mat if __name__ == "__main__": n = 5 magicSquare = generateSquare(n) for i in range(n): for j in range(n): print(magicSquare[i][j], end=" ") print()
C# using System; using System.Collections.Generic; class GfG { // A function to generate odd sized magic squares static List<List<int>> generateSquare(int n) { // initialize magic square List<List<int>> mat = new List<List<int>>(); for (int ii = 0; ii < n; ii++) { mat.Add(new List<int>()); for (int jj = 0; jj < n; jj++) mat[ii].Add(0); } // Initialize position for 1 int i = n / 2; int j = n - 1; // One by one put all values in magic square for (int num = 1; num <= n * n; num++) { // put the current element at (i, j) mat[i][j] = num; // if we get multiple of n, move left if (num % n == 0) { j--; } // else move to top-right else { i--; j++; } // add n and take modulo // to avoid out of bounds i += n; i %= n; j += n; j %= n; } return mat; } static void Main() { int n = 5; List<List<int>> magicSquare = generateSquare(n); for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { Console.Write(magicSquare[i][j] + " "); } Console.WriteLine(); } } }
JavaScript // A function to generate odd sized magic squares function generateSquare(n) { // initialize magic square let mat = []; for (let ii = 0; ii < n; ii++) { mat[ii] = []; for (let jj = 0; jj < n; jj++) mat[ii][jj] = 0; } // Initialize position for 1 let i = Math.floor(n / 2); let j = n - 1; // One by one put all values in magic square for (let num = 1; num <= n * n; num++) { // put the current element at (i, j) mat[i][j] = num; // if we get multiple of n, move left if (num % n === 0) { j--; } // else move to top-right else { i--; j++; } // add n and take modulo // to avoid out of bounds i += n; i %= n; j += n; j %= n; } return mat; } let n = 5; let magicSquare = generateSquare(n); for (let i = 0; i < n; i++) { let row = ""; for (let j = 0; j < n; j++) { row += magicSquare[i][j] + " "; } console.log(row.trim()); }
Output9 3 22 16 15 2 21 20 14 8 25 19 13 7 1 18 12 6 5 24 11 10 4 23 17
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Queries in a MatrixGiven two integers m and n, that describes the order m*n of a matrix mat[][], initially filled with integers from 1 to m*n sequentially in a row-major order. Also, there is a 2d array query[][] consisting of q queries, which contains three integers each, where the first integer t describes the type
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Find pairs with given sum such that elements of pair are in different rowsGiven a matrix of distinct values and a sum. The task is to find all the pairs in a given matrix whose summation is equal to the given sum. Each element of a pair must be from different rows i.e; the pair must not lie in the same row.Examples: Input : mat[][] = {{1, 3, 2, 4}, {5, 8, 7, 6}, {9, 10, 1
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Find all permuted rows of a given row in a matrixGiven a matrix mat[][] of order m*n, and an index ind. The task is to find all the rows in the matrix mat[][] which are permutations of rows at index ind.Note: All the elements of a row are distinct.Examples: Input: mat[][] = [[3, 1, 4, 2], [1, 6, 9, 3], [1, 2, 3, 4], [4, 3, 2, 1]] ind = 3 Output: 0
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Find number of transformation to make two Matrix EqualGiven two matrices a and b of size n*m. The task is to find the required number of transformation steps so that both matrices become equal. Print -1 if this is not possible. The transformation step is as follows: Select any one matrix out of two matrices. Choose either row/column of the selected mat
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Inplace (Fixed space) M x N size matrix transposeGiven an M x N matrix, transpose the matrix without auxiliary memory.It is easy to transpose matrix using an auxiliary array. If the matrix is symmetric in size, we can transpose the matrix inplace by mirroring the 2D array across it's diagonal (try yourself). How to transpose an arbitrary size matr
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Minimum flip required to make Binary Matrix symmetricGiven a Binary Matrix mat[][] of size n x n, consisting of 1s and 0s. The task is to find the minimum flips required to make the matrix symmetric along the main diagonal.Examples : Input: mat[][] = [[0, 0, 1], [1, 1, 1], [1, 0, 0]];Output: 2Value of mat[1][0] is not equal to mat[0][1].Value of mat[2
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Magic Square of Odd OrderGiven a positive integer n, your task is to generate a magic square of order n * n. A magic square of order n is an nâ¯*â¯n grid filled with the numbers 1 through n² so that every row, every column, and both main diagonals each add up to the same total, called the magic constant (or magic sum) M. Beca
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Hard problems on Matrix
Number of IslandsGiven an n x m grid of 'W' (Water) and 'L' (Land), the task is to count the number of islands. An island is a group of adjacent 'L' cells connected horizontally, vertically, or diagonally, and it is surrounded by water or the grid boundary. The goal is to determine how many distinct islands exist in
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A Boolean Matrix QuestionGiven a boolean matrix mat where each cell contains either 0 or 1, the task is to modify it such that if a matrix cell matrix[i][j] is 1 then all the cells in its ith row and jth column will become 1.Examples:Input: [[1, 0], [0, 0]]Output: [[1, 1], [1, 0]]Input: [[1, 0, 0, 1], [0, 0, 1, 0], [0, 0, 0
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Matrix Chain MultiplicationGiven the dimension of a sequence of matrices in an array arr[], where the dimension of the ith matrix is (arr[i-1] * arr[i]), the task is to find the most efficient way to multiply these matrices together such that the total number of element multiplications is minimum. When two matrices of size m*
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Maximum size rectangle binary sub-matrix with all 1sGiven a 2d binary matrix mat[][], the task is to find the maximum size rectangle binary-sub-matrix with all 1's. Examples: Input: mat = [ [0, 1, 1, 0], [1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 0, 0] ]Output : 8Explanation : The largest rectangle with only 1's is from (1, 0) to (2, 3) which is[1, 1, 1, 1][
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Construct Ancestor Matrix from a Given Binary TreeGiven a Binary Tree where all values are from 0 to n-1. Construct an ancestor matrix mat[n][n] where the ancestor matrix is defined as below. mat[i][j] = 1 if i is ancestor of jmat[i][j] = 0, otherwiseExamples: Input: Output: {{0 1 1} {0 0 0} {0 0 0}}Input: Output: {{0 0 0 0 0 0} {1 0 0 0 1 0} {0 0
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K'th element in spiral form of matrixGiven a matrix of size n * m. You have to find the kth element which will obtain while traversing the matrix spirally starting from the top-left corner of the matrix.Examples:Input: mat[][] = [ [1, 2, 3], [4, 5, 6], [7, 8, 9] ], k = 4Output: 6Explanation: Spiral traversal of matrix: {1, 2, 3, 6, 9,
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Largest Plus or '+' formed by all ones in a binary square matrixGiven an n à n binary matrix mat consisting of 0s and 1s. Your task is to find the size of the largest â+â shape that can be formed using only 1s. A â+â shape consists of a center cell with four arms extending in all four directions (up, down, left, and right) while remaining within the matrix bound
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Shortest path in a Binary MazeGiven an M x N matrix where each element can either be 0 or 1. We need to find the shortest path between a given source cell to a destination cell. The path can only be created out of a cell if its value is 1.Note: You can move into an adjacent cell in one of the four directions, Up, Down, Left, and
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Maximum sum square sub-matrix of given sizeGiven a 2d array mat[][] of order n * n, and an integer k. Your task is to find a submatrix of order k * k, such that sum of all the elements in the submatrix is maximum possible.Note: Matrix mat[][] contains zero, positive and negative integers.Examples:Input: k = 3mat[][] = [ [ 1, 2, -1, 4 ] [ -8,
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Validity of a given Tic-Tac-Toe board configurationA Tic-Tac-Toe board is given after some moves are played. Find out if the given board is valid, i.e., is it possible to reach this board position after some moves or not.Note that every arbitrary filled grid of 9 spaces isn't valid e.g. a grid filled with 3 X and 6 O isn't valid situation because ea
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Minimum Initial Points to Reach DestinationGiven a m*n grid with each cell consisting of positive, negative, or no points i.e., zero points. From a cell (i, j) we can move to (i+1, j) or (i, j+1) and we can move to a cell only if we have positive points ( > 0 ) when we move to that cell. Whenever we pass through a cell, points in that cel
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Program for Sudoku GeneratorGiven an integer k, the task is to generate a 9 x 9 Sudoku grid having k empty cells while following the below set of rules:In all 9 submatrices 3x3, the elements should be 1-9, without repetition.In all rows, there should be elements between 1-9, without repetition.In all columns, there should be e
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