Is Prime

Checking Prime Numbers

Prime numbers are natural numbers greater than 1 that have no positive divisors other than 1 and themselves. Determining whether a number is prime is a fundamental problem in number theory and has applications in various fields, including cryptography and computer science.

In this challenge, you will implement a function to check if a given number is prime. You will use logical operators and conditional statements to handle the multiple conditions required to identify a prime number efficiently.

Your task

Your task is to complete the function is_prime(n: u32) -> bool that takes an unsigned integer n and returns a boolean value indicating whether n is a prime number.

Requirements

The function should return true if n is a prime number and false otherwise.
A prime number is a natural number greater than 1 that is not divisible by any number other than 1 and itself.
Use logical operators and conditional statements to check the conditions for a prime number.
Optimize the function to minimize unnecessary checks.

Example

let result = is_prime(5);
assert_eq!(result, true);
 
let result = is_prime(4);
assert_eq!(result, false);

Hints

Any number less than 2 is not prime.
The number 2 is the only even prime number.
For any other even number greater than 2, return false.
Check divisibility starting from 3 up to the square root of the number.

Editor not available on Mobile!

In order to solve the challenge, please visit this page on a desktop computer.

Solutions

Enriko

rix71

8 hours ago

3.24ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n == 2 {
        return true;
    }
    if n < 2 {
        return false;
    } 
    
    if n % 2 == 0 {
        return false;
    }
    for d in 3..((n as f32).sqrt() as u32) + 1 {
        if n % d == 0 {
            return false;
        }
    }
    true
}

Degisew Mengist

degisew

6 days ago

3.61ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n <= 1 {
        return false
    }
    for i in 2..=((n as f64).sqrt() as u32) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

Rajat Sharma

rajatsharma

9 days ago

4.32ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n < 2 {
        return false;
    }
    if n == 2 {
        return true;
    }
    if n % 2 == 0 {
        return false;
    }
    let mut i = 2.;
    let limit: f32 = (n as f32).sqrt();
    while i <= limit {
        if i % limit == 0. {
            return false;
        }
        i = i + 1.;
    }
    true
}

wertion555

12 days ago

3.48ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n == 1 {
        return false;
    }
    if n == 2 {
        return true;
    }
    for i in 2..n{
        if n % i == 0{
            return false;
        }
    }
    true
}

Hung Dinh

nhdinh

12 days ago

3.64ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n == 2 {
        return true;
    } else if n < 2 || n > 2 && n % 2 == 0 {
        return false;
    } else {
        for m in 3..=(n as f32).sqrt() as u32 {
            if n % m == 0 {
                return false;
            }
        }
        return true;
    }
}

MrGru

23 days ago

2.80ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {
        return false;
    }
    if n == 2 {
        return true;
    }
    for i in 2..n {
        if n % i == 0 {
            return false;
        }
    }
    return true;
}

John Adams

netik

a month ago

4.03ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n < 2 {
        return false;
    }
    for i in 2..=(n as f64).sqrt() as u32 {
        if n % i == 0 {
            return false;
        }
    }
    return true;
}

Jakub Wiśniewski

wisniewskij

a month ago

3.80ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n < 2 {
        return false;
    }
    for i in 2..=(n as f64).sqrt() as u32 {
        if n % i == 0 {
            return false;
        }
    }
    return true;
}

Jason

Jason-fy-wang

a month ago

3.79ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n <= 1 {
        return false;
    }
    for i in 1..=((n as f64).sqrt() as u32) {
        if n % i == 0 && i != 1 {
            return false;
        }
    }
    true
}

roboquaternion

a month ago

3.19ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    // Early return for known prime, 2.
    if n == 2 {
        return true
    }
    // Early return for known non-primes.
    if n < 2 || (n%2 ==0) {
        return false
    }
    
    // Get the square root as u8. Add 1 due to integer rounding.
    let root_n = ((n as f64).sqrt()) as u32 + 1;
    // Check all the divisiors from 3, 5, 7, ... sqrt(n). There is no need to check 4, 6, 8, etc because we already did that above.
    for divisor in (3..root_n).step_by(2) {
        if n % divisor == 0 {
            return false
        }
    }
    return true
}

roboquaternion

a month ago

2.88ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {
        return false
    }
    // Get the square root as u8. Add 1 due to integer rounding.
    let root_n = ((n as f64).sqrt()) as u32 + 1;
    for divisor in 2..root_n {
        if n % divisor == 0 {
            return false
        }
    }
    return true
}

mhd242006

a month ago

2.82ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n <= 1 {
        return false;
    }
    for i in 2..n {
        if n % i == 0 {
           return  false; 
        }
    }
    true
}

Deaddy3

a month ago

4.77ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {
        return false;
    }
    if n == 2 {
        return true;
    }
    for i in 2..(((n as f32).sqrt()) as u32 + 1) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

vijayabhaskar badireddi

ptcte

a month ago

3.44ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    let mut index: u32 = 2;
    if n < 2 {
        return false;
    }
    
    while index * index <= n {
        if n % index == 0 {
            return false;
        }
        index += 1;
    }
    true
}

Aurimas Kuniutis

auriku

a month ago

2.94ms

81.43kb

    pub fn is_prime(n: u32) -> bool {
        if n < 2 || n % 2 == 0 && n != 2 {
            return false;
        } else {
            for d in 2..(n as f32).sqrt() as u32 + 1 {
                if n % d == 0 {
                    return false;
                }
            }
        }
        true
    }

Jason

chenjie1219

a month ago

4.30ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n <= 1 {
        return false;
    }
    
    // 将循环范围优化为 2..=sqrt(n)，时间复杂度降为 O(√n)
    let sqrt_n = (n as f64).sqrt() as u32;
    for i in 2..=sqrt_n {
        if n % i == 0 {
            return false;
        }
    }
    true
}

Jason

chenjie1219

a month ago

4.77ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n <= 1 {
        return false;
    }
    for i in 2..n {
        if n % i == 0 {
            return false;
        }
    }
    true
}

Marcel Schiffel

mschiffel

a month ago

3.44ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n {
        1 => return false,
        2 => return true,
        _ => {},
    }
    for i in 2..n {
        if n % i == 0 {
            return false
        }
    }
    true
}

javad05

a month ago

3.63ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n ==1{
        return false;
    }
    for i in 2..=(n/2){
        if n%i==0{
            return false;
        }
    }
    true
}

javad05

a month ago

3.45ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n <2{
        return false;
    }
    for i in 2..=(n/2){
        if n%i==0{
            return false;
        }
    }
    true
}

javad05

a month ago

21.92ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n <2{
        return false;
    }
    for i in 2..=(n/2){
        if n%i==0{
            return false;
        }
    }
    true
}

javad05

a month ago

3.14ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n ==1{
        return false;
    }
    for i in 2..=(n/2){
        if n%i==0{
            return false;
        }
    }
    true
}

Robbie K

va1ha11a

2 months ago

3.98ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n {
        0..=1 => false,
        2 => true,
        _ => checkaroo(n),
    }
}
fn checkaroo(n: u32) -> bool {
    let max = (n as f64).sqrt() as u32;
    for c in 2..max + 1 {
        if n % c == 0 {return false}
    };
    true
}

syberianbull

2 months ago

3.46ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match (n, n % 2) {
        (0..= 1, _) => false,
        (2, _) => true,
        (_, 0) => false,
        _ => {
            //let max = n.isqrt();
            let max = (n as f64).sqrt() as u32; //n.isqrt();
            for i in 2..= max {
                if n % i == 0 {
                    return false
                }
            }
            true
        }
    }
}

endrin

2 months ago

3.73ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n <= 1 || (n > 2 && n % 2 == 0) { return false };
    for p in (3..=(n / 2)).step_by(2) {
        if n % p == 0 { return false }
    }
    true
}

VerweyFr

2 months ago

5.20ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n {
        0 => false,
        1 => false,
        x => {
            for i in 2..n {
                if n % i == 0 {
                    return false
                }
            }
            true
        }
    }
}

Yixian Du

duyixian1234

2 months ago

5.78ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    n > 1 && (2..=(n as f64).sqrt() as u32).all(|i| n % i != 0)
}

delxs

2 months ago

3.31ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    n > 1 && (2..=(n as f64).sqrt() as u32).all(|i| n % i != 0)
}

Artem

tich31337

2 months ago

3.88ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        m if m < 2 => false,
        m if m == 2 => true,
        m if m % 2 == 0 => false,
        m => !(3..=((n as f64).sqrt() as u32)).step_by(2).any(|x| m % x == 0),
    }
}

Ahmed Hassan

ahah43

2 months ago

2.99ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n{
        m if m < 2 => false,
        m if m == 2 => true,
        m if m > 2 && m %2 ==0 => false,
        m => !(3..=((m as f64).sqrt() as u32)).step_by(2).any(|s| m%s==0)
    } 
}

lugtester

2 months ago

3.51ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        0 => false,
        1 => false,
        2 => true,
        x => {  for i in 2..x {
                    if x%i == 0 {
                        return false;
                    }   
                }
            true 
        }
    }
}

Elias Schuler

elE0710

2 months ago

7.83ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n == 1
    {
        return false;
    }
    if n == 2
    {
        return true;
    }
    for i in 2..=(n/2)
    {
        if n % i == 0
        {
            return false;
        }
    }
    return true;
}

panda wiz

pandamrx

2 months ago

3.53ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    !(n < 2 || (n % 2 == 0 && n != 2) || (n % 3 == 0 && n != 3) || (n % 5 == 0 && n != 5) || (n % 7 == 0 && n != 7))
}

hex-order

idan-KH

2 months ago

2.79ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n  < 2 {
        return false;
    }
    
    for number in 2..n {
        if n % number == 0 {
            return false;
        }
    }
    return true;
}

Anna Komarova

Vlasanya

2 months ago

3.28ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n < 2 {
        return false;
    }
    if n == 2 {
        return true;
    }
    if n % 2 == 0 {
        return false;
    }
    let limit = (n as f64).sqrt() as u32;
    let mut i = 3;
    while i <= limit {
        if n % i == 0 {
            return false;
        }
        i += 2;
    }
    true
}

Icarus

IcarusxB

2 months ago

5.11ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n <= 1 {
        return false;
    }
    if n == 2 {
        return true;
    }
    if n % 2 == 0 {
        return false;
    }
    let limit = (n as f64).sqrt() as u32;
    for i in (3..=limit).step_by(2) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

no-yan

2 months ago

3.72ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    let lim = (n as f64).sqrt() as u32;
    if n == 1 {
        return false
    }
    for i in 2..=lim {
        if n%i == 0 {
           return false
        }
    }
    true   
}

no-yan

2 months ago

3.06ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    let lim = (n as f64).sqrt() as u32;
    if n == 1 {
        return false
    }
    for i in 2..=lim {
        if n%i == 0 {
           return false
        }
    }
    true   
}

AnKarl

Zythophilus

2 months ago

3.39ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n > 1 {
        if n == 2 {
            return true
        } 
        if n % 2 == 0 {
            return false
        }
        for num in 3..((n as f64).sqrt() as u32 + 1) {
            if n % num == 0 {
                return false
            }
        }
        true
    } else {
        false
    }
}

Dhananjay Pandit

djpandit007

2 months ago

3.75ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {
        return false;
    } else if n == 2 {
        return true;
    } else if n % 2 == 0 {
        return false;
    }
    for divisor in 3..=((n as f64).sqrt() as u32 + 1) {
        if n % divisor == 0 {
            return false;
        }
    }
    return true;
}

vojta stefan

vojtastefan

2 months ago

3.44ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
     match n {
        n if n < 2 => false,
        
        _ => {
            for i in 2..=(n as f64).sqrt() as u32 {
                if i == n {
                    continue;
                }
                if n % i == 0 {
                    return false;
                }
            }
            true
        }
    }
}

hemulya

3 months ago

3.62ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n < 2 {
        return false;
    }
    if n % 2 == 0 {
        return n == 2
    }
    let mut i = 3;
    let sqrt_n = (n as f64).sqrt() as u32;
    while i <= sqrt_n {
        if n % i == 0 {
            return false;
        }
        i += 2;
    }
    true
}

Ayushman Rathore

Spartan09

3 months ago

4.00ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n {
        n if n < 2 => false,
        2 => true,
        n if n % 2 == 0 => false,
        n => {
            for i in 3..=(n as f64).sqrt() as u32 {
                if i == n { continue; }
                if n % i == 0 { return false }
            }
            true
        }
    }
}

Lucas Deprit

lucasdeprit

3 months ago

3.56ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        1 => false,
        2 => true,
        n if n % 2 == 0 => false,
        _ => {
           let sqrt_from_n = (n as f64).sqrt() as u32 ;
            let mut result_bool: bool = true; 
            for i in 2..=sqrt_from_n {
                if sqrt_from_n * i == n {
                    result_bool = false;
                }
            }
            result_bool 
        }
    }
}

Manuel Manjarres R.

manuelmj

3 months ago

2.97ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        1 => false,
        2 => true,
        n if n % 2 == 0 => false, 
        _ => {
            let sqrt_from_n = (n as f64).sqrt() as u32 ;
            let mut result_bool: bool = true; 
            for i in 2..=sqrt_from_n {
                if sqrt_from_n * i == n {
                    result_bool = false;
                }
            }
            result_bool
        } 
    }
}

Trevor Kann

TrevorGKann

3 months ago

3.16ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {return false};
    if n < 4 {return true}
    let mut index = 2;
    loop {
        if n % index == 0 { return false };
        if index * index > n { return true };
        index += 1;
    }
}

Éric Villani

TheTrueCaligari

3 months ago

4.29ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n % 2 == 0 {
        n == 2
    } else {
        if n == 1 {
            false
        } else {
            let mut is_p = true;
            let mut d = 3;
            while is_p && d*d <= n {
                if n % d == 0 {
                    is_p = false;
                } else {
                    d += 2;
                }
            }
            is_p
        }
    }
}

Yi Hao

leongyihao

3 months ago

3.10ms

81.43kb

pub fn is_prime(n: u32) -> bool {
	if n < 2 {
		false
	}
	else {
		(2..n).find(|i| 0 == n % i).is_none()
	}
}

Jordan

Jordan-Haidee

3 months ago

3.08ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {
        return false;
    }
    if n == 2 {
        return true;
    }
    let max = (n as f32).sqrt() as u32;
    for i in 2..=max {
        if n % i == 0 {
            return false;
        }
    }
    return true;
}

Nikita Smirnov

Nismirno

3 months ago

13.31ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    let root = (n as f64).sqrt();
    match n {
        0 | 1 => {
            return false;
        }
        2 => {
            return true;
        }
        _ => {
            if n % 2 == 0 {
                return false;
            }
            for i in (3..=(root as u32)).step_by(2) {
                if n % i == 0 {
                    return false;
                }
            }
        }
    }
    true
}