HACKERRANK.COM => PROJECTEULER SOLUTION # 3

_{This problem is a programming version of Problem 3 from projecteuler.net}

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of a given number N?

Input Format
First line contains T, the number of test cases. This is followed by T lines each containing an integer N.

Output Format
For each test case, display the largest prime factor of N.

Constraints
1≤T≤10
10≤N≤1012

Sample Input

2

10

17

Sample Output

5

17

First of all I submitted this code and this code showed Time limit exceeded in test case 5.

So this is not the most efficient code to find the largest prime factor of a given number.

/*****************************************************/

#include<stdio.h>

int isPrime(long long int n)

{

    long long int i;

    for(i=2;i*i<=n;i++)

        if(n%i==0)

            return 0;

    return 1;

}

long long int findLargestPrimeFactor(long long int n)

{

    long long int counter=3;

    while(n%2==0)

        n/=2;

    if(n==1)

        return 2;

    while(n!=1)

    {

        if(isPrime(n))

            return n;

        while(n%counter==0)

            n/=counter;

        counter+=2;

   }

   return counter-2;

}

int main()

{

    int t;

    long long int n;

    scanf("%d",&t);

    while(t--)

    {

        scanf("%lld",&n);

        printf("%lld\n",findLargestPrimeFactor(n));

    }

    return 0;

}

/*****************************************************/