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Sunday, 10 September 2017

GCD (HCF) of N Integers


GCD (HCF) of N Integers

N integers are passed as input to the program. The program must print the GCD (HCF) of these N integers.
Input Format:
The first line contains N.
The second line contains N integers each separated by a space.
Output Format:
The first line contains the HCF of these N numbers.
Boundary Conditions:
2 <= N <= 100
Example Input/Output 1:
Input:
4
15 20 30 50
Output:
5

Code:
#include <iostream>

using namespace std;
int gcd(int a, int b)
{
    if(a==0)
        return b;
    return gcd(b%a,a);
}
int main(int argc, char** argv)
{
int n,i;
cin>>n;
int arr[n];
cin>>arr[0];
int res=arr[0];
for(i=1;i<n;i++)
{
    cin>>arr[i];
    res=gcd(arr[i],res);
}
cout<<res;
}

Please do comment If u have any Queries!

2 comments:

  1. Why did you assign int res=arr[0];? Please explain me.

    ReplyDelete
  2. The GCD of three or more numbers equals the product of the prime factors common to all the numbers, but it can also be calculated by repeatedly taking the GCDs of pairs of numbers.

    gcd(a, b, c) = gcd(a, gcd(b, c))
    = gcd(gcd(a, b), c)
    = gcd(gcd(a, c), b)
    For an array of elements, we do following.

    result = arr[0]
    For i = 1 to n-1
    result = GCD(result, arr[i])

    ReplyDelete

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