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 matrixMAX=100 # Function for calculating frequencydef 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 codem = 3n = 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 frequencydef 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 codem = 3n = 3 array = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] freq(array, m, n)# This code is contributed# by vinay pinjala. |
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.
- Start with a matrix of size m x n.
- Flatten the matrix into a 1D list using list comprehension.
- Initialize two variables, odd_freq, and even_freq, to 0.
- 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.
- Print the frequency of odd and even numbers.
Python3
# Example input matrixmatrix = [[10, 11, 12], [13, 14, 15], [16, 17, 18]]# Using list comprehension to flatten# the matrix into a 1D listflat_list = [num for row in matrix for num in row]# Finding the frequenciesodd_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 outputprint("Frequency of odd numbers:", odd_freq)print("Frequency of even numbers:", even_freq) |
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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