Euler Project #3 Largest prime factor Timeout












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I have been recently trying my hands on Euler's Project through HackerRank and got stuck with project #3 where you have to find the Largest Prime Factor.



Question: The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of a given number N?



I have written two different codes which both works for the first four problems in HackerRank but timeout on the last two. Please let me know how I can optimize my code further so that the timeout doesn't occur.



Code #1



for a in range(int(input())):
n = int(input())
b = n//2
i=1
if b%2==1:
i+=1
max=1
while b > 2:
if n%b==0:
isprime = True
for c in range(2,int(b**0.5)+1):
if b%c==0:
isprime = False
break;
if isprime:
max = b
break;
b-=i
if max==1:
max=n
print(max)


This one tries to find the first largest numbers which can divide a particular number and then tries to find whether it is a prime.



Code #2



for a in range(int(input())):
n = int(input())
num = n
b = 2
max=1
while n > 1 and b < (num//2)+1:
if n%b==0:
n//=b
max=b
b+=1
if max==1:
max=n
print(max)


This basically tries to find the last largest factor by multiple division.









share



























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    I have been recently trying my hands on Euler's Project through HackerRank and got stuck with project #3 where you have to find the Largest Prime Factor.



    Question: The prime factors of 13195 are 5, 7, 13 and 29.
    What is the largest prime factor of a given number N?



    I have written two different codes which both works for the first four problems in HackerRank but timeout on the last two. Please let me know how I can optimize my code further so that the timeout doesn't occur.



    Code #1



    for a in range(int(input())):
    n = int(input())
    b = n//2
    i=1
    if b%2==1:
    i+=1
    max=1
    while b > 2:
    if n%b==0:
    isprime = True
    for c in range(2,int(b**0.5)+1):
    if b%c==0:
    isprime = False
    break;
    if isprime:
    max = b
    break;
    b-=i
    if max==1:
    max=n
    print(max)


    This one tries to find the first largest numbers which can divide a particular number and then tries to find whether it is a prime.



    Code #2



    for a in range(int(input())):
    n = int(input())
    num = n
    b = 2
    max=1
    while n > 1 and b < (num//2)+1:
    if n%b==0:
    n//=b
    max=b
    b+=1
    if max==1:
    max=n
    print(max)


    This basically tries to find the last largest factor by multiple division.









    share

























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      0








      I have been recently trying my hands on Euler's Project through HackerRank and got stuck with project #3 where you have to find the Largest Prime Factor.



      Question: The prime factors of 13195 are 5, 7, 13 and 29.
      What is the largest prime factor of a given number N?



      I have written two different codes which both works for the first four problems in HackerRank but timeout on the last two. Please let me know how I can optimize my code further so that the timeout doesn't occur.



      Code #1



      for a in range(int(input())):
      n = int(input())
      b = n//2
      i=1
      if b%2==1:
      i+=1
      max=1
      while b > 2:
      if n%b==0:
      isprime = True
      for c in range(2,int(b**0.5)+1):
      if b%c==0:
      isprime = False
      break;
      if isprime:
      max = b
      break;
      b-=i
      if max==1:
      max=n
      print(max)


      This one tries to find the first largest numbers which can divide a particular number and then tries to find whether it is a prime.



      Code #2



      for a in range(int(input())):
      n = int(input())
      num = n
      b = 2
      max=1
      while n > 1 and b < (num//2)+1:
      if n%b==0:
      n//=b
      max=b
      b+=1
      if max==1:
      max=n
      print(max)


      This basically tries to find the last largest factor by multiple division.









      share














      I have been recently trying my hands on Euler's Project through HackerRank and got stuck with project #3 where you have to find the Largest Prime Factor.



      Question: The prime factors of 13195 are 5, 7, 13 and 29.
      What is the largest prime factor of a given number N?



      I have written two different codes which both works for the first four problems in HackerRank but timeout on the last two. Please let me know how I can optimize my code further so that the timeout doesn't occur.



      Code #1



      for a in range(int(input())):
      n = int(input())
      b = n//2
      i=1
      if b%2==1:
      i+=1
      max=1
      while b > 2:
      if n%b==0:
      isprime = True
      for c in range(2,int(b**0.5)+1):
      if b%c==0:
      isprime = False
      break;
      if isprime:
      max = b
      break;
      b-=i
      if max==1:
      max=n
      print(max)


      This one tries to find the first largest numbers which can divide a particular number and then tries to find whether it is a prime.



      Code #2



      for a in range(int(input())):
      n = int(input())
      num = n
      b = 2
      max=1
      while n > 1 and b < (num//2)+1:
      if n%b==0:
      n//=b
      max=b
      b+=1
      if max==1:
      max=n
      print(max)


      This basically tries to find the last largest factor by multiple division.







      python beginner python-3.x programming-challenge





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      remedcuremedcu

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