# Python Program for Frequencies of even and odd numbers in a matrix

Given a matrix of order m*n then the task is to find the frequency of even and odd numbers in matrix
Examples:

```Input : m = 3, n = 3
{ 1, 2, 3 },
{ 4, 5, 6 },
{ 7, 8, 9 }
Output : Frequency of odd number =  5
Frequency of even number = 4

Input :   m = 3, n = 3
{ 10, 11, 12 },
{ 13, 14, 15 },
{ 16, 17, 18 }
Output : Frequency of odd number  =  4
Frequency of even number  = 5```

## Python3

 `# Python Program to Find the frequency` `# of even and odd numbers in a matrix`   `MAX``=``100` ` `  `# Function for calculating frequency` `def` `freq(ar, m, n):` `    ``even ``=` `0` `    ``odd ``=` `0` `     `  `    ``for` `i ``in` `range``(m):` `        ``for` `j ``in` `range``(n):` `        `  `            ``# modulo by 2 to check` `            ``# even and odd` `            ``if` `((ar[i][j] ``%` `2``) ``=``=` `0``):` `                ``even ``+``=` `1` `            ``else``:` `                ``odd ``+``=` `1` `     `  `    ``# print Frequency of numbers` `    ``print``(``" Frequency of odd number ="``, odd)` `    ``print``(``" Frequency of even number ="``, even)`   ` `  `# Driver code` `m ``=` `3` `n ``=` `3`    `     `  `array ``=` `[ [ ``1``, ``2``, ``3` `],` `        ``[ ``4``, ``5``, ``6` `],` `        ``[ ``7``, ``8``, ``9` `] ]` ` `  `freq(array, m, n)`   `# This code is contributed` `# by Anant Agarwal.`

Output:

``` Frequency of odd number = 5
Frequency of even number = 4```

Time Complexity: O(m*n)
Auxiliary Space: O(1)

Please refer complete article on Frequencies of even and odd numbers in a matrix for more details!

## Python3

 `# Python Program to Find the frequency` `# of even and odd numbers in a matrix using bitwise & operator.`   `MAX``=``100` ` `  `# Function for calculating frequency` `def` `freq(ar, m, n):` `    ``even ``=` `0` `    ``odd ``=` `0` `     `  `    ``for` `i ``in` `range``(m):` `        ``for` `j ``in` `range``(n):` `        `  `            ``# bitwise & 1 to check` `            ``# even and odd` `            ``if` `((ar[i][j] & ``1``) ``=``=` `0``):` `                ``even ``+``=` `1` `            ``else``:` `                ``odd ``+``=` `1` `     `  `    ``# print Frequency of numbers` `    ``print``(``" Frequency of odd number ="``, odd)` `    ``print``(``" Frequency of even number ="``, even)`   ` `  `# Driver code` `m ``=` `3` `n ``=` `3`    `     `  `array ``=` `[ [ ``1``, ``2``, ``3` `],` `        ``[ ``4``, ``5``, ``6` `],` `        ``[ ``7``, ``8``, ``9` `] ]` ` `  `freq(array, m, n)`   `# This code is contributed` `# by vinay pinjala.`

Output

``` Frequency of odd number = 5
Frequency of even number = 4```

Time Complexity: O(m*n)
Auxiliary Space: O(1)

#### Approach#3: Using sum

We start by defining the input matrix. We use list comprehension to flatten the matrix into a 1D list. We then use the sum() function along with a generator expression to count the number of odd and even numbers in the flattened list. Finally, we print the frequency of odd and even numbers.

2. Flatten the matrix into a 1D list using list comprehension.
3. Initialize two variables, odd_freq, and even_freq, to 0.
4. Iterate through the flattened list and increment odd_freq by 1 if the element is odd, and increment even_freq by 1 if the element is even.
5. Print the frequency of odd and even numbers.

## Python3

 `# Example input matrix` `matrix ``=` `[[``10``, ``11``, ``12``],` `          ``[``13``, ``14``, ``15``],` `          ``[``16``, ``17``, ``18``]]`   `# Using list comprehension to flatten` `# the matrix into a 1D list` `flat_list ``=` `[num ``for` `row ``in` `matrix ``for` `num ``in` `row]`   `# Finding the frequencies` `odd_freq ``=` `sum``(``1` `for` `num ``in` `flat_list ``if` `num ``%` `2` `!``=` `0``)` `even_freq ``=` `sum``(``1` `for` `num ``in` `flat_list ``if` `num ``%` `2` `=``=` `0``)`   `# Printing the output` `print``(``"Frequency of odd numbers:"``, odd_freq)` `print``(``"Frequency of even numbers:"``, even_freq)`

Output

```Frequency of odd numbers: 4
Frequency of even numbers: 5```

Time Complexity; O(n2), where n is the length of one side of the matrix. This is because the program iterates over each element in the matrix once.

Space Complexity: O(n2), since it creates a 1D list with n^2 elements to store the flattened matrix. However, the space required for the odd_freq and even_freq variables is constant, since they only store two integers.

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