Open In App
Related Articles

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

Improve Article
Improve
Save Article
Save
Like Article
Like

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!

Method: Using bitwise & operator

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.

  1. Start with a matrix of size m x n.
  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.


Feeling lost in the world of random DSA topics, wasting time without progress? It's time for a change! Join our DSA course, where we'll guide you on an exciting journey to master DSA efficiently and on schedule.
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 geeks!

Last Updated : 21 Apr, 2023
Like Article
Save Article
Similar Reads
Related Tutorials