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Python program to find the LCM of the array elements

Here, we will learn how to find the LCM (lowest common multiple) of the arrays elements in the Python programming language?
Submitted by Bipin Kumar, on November 19, 2019

What is LCM?

LCM is the lowest multiple of two or more numbers. Multiples of a number are those numbers which when divided by the number leave no remainder. When we are talking about the multiple, we consider only the positive number. For example, the LCM of 12 and 48 is 48 because 48 is 4^th multiple of 12 and 48 is 1^st multiple of 48.

Problem statement

Here, an array of positive elements will be provided by the user and we have to find the LCM of the elements of the array by using the Python. To find LCM of the elements of the array, use the following algo,

Algorithm to find the LCM of array elements

The algorithm to find the LCM of array elements is:

• We need to import the math module to find the GCD of two numbers using math.gcd() function.
• At first, find the LCM of initial two numbers using: LCM(a,b) = a*b/GCD(a,b). And, then find the LCM of three numbers with the help of LCM of first two numbers using LCM(ab,c) = lcm(lcm(a1, a2), a3). The same concept we have implemented.

Now, we will write the Python program in a simple way by implementing the above algorithm.

Python program to find the LCM of the array elements

# importing the module
import math

# function to calculate LCM
def LCMofArray(a):
  lcm = a[0]
  for i in range(1,len(a)):
    lcm = lcm*a[i]//math.gcd(lcm, a[i])
  return lcm


# array of integers
arr1 = [1,2,3]
arr2 = [2,3,4]
arr3 = [3,4,5]
arr4 = [2,4,6,8]
arr5 = [8,4,12,40,26,28]

print("LCM of arr1 elements:", LCMofArray(arr1))
print("LCM of arr2 elements:", LCMofArray(arr2))
print("LCM of arr3 elements:", LCMofArray(arr3))
print("LCM of arr4 elements:", LCMofArray(arr4))
print("LCM of arr5 elements:", LCMofArray(arr5))

Output

LCM of arr1 elements: 6
LCM of arr2 elements: 12
LCM of arr3 elements: 60
LCM of arr4 elements: 24
LCM of arr5 elements: 10920

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