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

Arpan Shingala

arpan-vs

5 days ago

4.11ms

81.43kb

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

amdfxlucas

6 days ago

3.07ms

81.43kb

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

GunGraveCpp

6 days ago

4.82ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n {
        0 | 1 => false,
        2 | 3 => true,
        _ => {
            let mid = (n as f32).sqrt().ceil() as u32;
            for i in 2..=mid {
                if n % i == 0 {
                    return false;
                }
            }
            return true;
        }
    }
}

manu3618

10 days ago

3.11ms

81.43kb

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

aghia98

11 days ago

3.37ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        0 | 1 => false,
        2 => true,
        _ => {
            let mut found = false;
            for i in 2..n {
                if n%i ==0 {
                    found = true;
                    break;
                }
            }
            !found
        }
    }
}

Christophe Pronier

chrpron

19 days ago

3.02ms

81.43kb

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

Walter White

durgaprasad118

20 days ago

4.35ms

81.43kb

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

bzdula

21 days ago

3.03ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n {
        0 | 1 => false,
        2 | 3 => true,
        _ if n % 2 == 0 => false,
        _ => !(2..n).any(|i| n % i == 0),
    }
}

Ranjith Thangavel

RanjithECE24

24 days ago

2.82ms

81.43kb

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

Wouter

WouterMartens

a month ago

4.81ms

81.43kb

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

whhc

a month ago

3.23ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n < 2 {
        false
    } else if n == 2 {
        true
    } else {
        let count = (2..=n)
            .map(|i| n % 2 != 0 && n % i == 0)
            .filter(|b| *b)
            .count();
        if count == 1 {
            true
        } else {
            false
        }
    }
}

Sandeep chauhan

ryzen-xp

a month ago

3.09ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n == 2 {
       return  true; 
    }
    else if n< 2 ||  n%2 == 0 {
        return false; 
    }
    let mut  i = 3 ;
   while i <= n / i {
        if n % i == 0 {
            return false;
        }
        i += 2;
    }
    true
}

Andy Randrianirina

andyslash

a month ago

4.14ms

81.43kb

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

Heino Mortensen

hmortensen83

a month ago

3.04ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n == 2 {
        return true;
    } else if n < 2 || n % 2 == 0 {
        return false;
    }
    let mut i = 3;
    while i <= n / i {
        if n % i == 0 {
            return false;
        }
        i += 2;
    }
    true
}

cremno

a month ago

3.00ms

81.43kb

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

Aniket Varma

aniketvarma

a month ago

3.26ms

81.43kb

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

medzernik

a month ago

3.03ms

81.43kb

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

Baron Curtin

baroncurtin2

a month ago

2.96ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n <= 1 {
        return false;
    }
    if n <= 3 {
        return true;
    }
    if (n % 2 == 0) || (n % 3 == 0) {
        return false;
    }
    // all primes > 3 are of the form 6k +- 1
    let mut i = 5;
    while i * i <= n {
        if n % i == 0 || n % (i + 2) == 0 {
            return false;
        }
        i += 6;
    }
    true
}

Evrins Hu

evrins

a month ago

3.11ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n <= 1 {
        return false;
    }
    if n == 2 {
        return true;
    }
    if n % 2 == 0 {
        return false;
    }
    let limit = (n as f32).sqrt() as u32;
    for i in (3..=limit).step_by(2) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

johndoe30bc

a month ago

3.05ms

81.43kb

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

xxxxsk

a month ago

3.53ms

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 sqrt_n = (n as f64).sqrt() as u32;
    for i in (3..=sqrt_n).step_by(2) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

Evgenii Grigorenko

grevgeny

a month ago

3.14ms

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 sqrt_n = (n as f64).sqrt() as u32;
    for i in (3..=sqrt_n).step_by(2) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

orao-pao

a month ago

3.16ms

86.83kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        0..=1 => false,
        2 => true,
        3.. => {
            let mut primes: Vec<u32> = Vec::new();
            primes.push(2);
            for i in (3..=n).step_by(2) {
                let mut not_a_prime = false;
                for j in primes.iter() {
                    if i % j == 0 {
                        not_a_prime = true;
                    }
                }
                if !not_a_prime {
                    primes.push(i);
                }
            }
            if n == *primes.last().unwrap() {
                true
            } else {
                false
            }
        }
    }
}

brucecox01

a month ago

2.81ms

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;
        }
    }
    return true;
}

Ashish Khare

ashishk1331

a month ago

3.48ms

81.43kb

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

pickbiest

a month ago

3.05ms

81.43kb

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

Krzysztof Atłasik

katlasik

2 months ago

3.31ms

90.36kb

pub fn is_prime(n: u32) -> bool {
    if n == 0 || n == 1 {
        false
    } else if n == 2 {
        return true
    } else {
        (2..n).into_iter().all(|x| { 
            println!("{} % {} = {}", n, x, n % x) ;
            n % x != 0 
            
        })
    }
    
    
}

Kr0wZ

2 months ago

3.29ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        number if number < 2 => false,
        2 => true,
        number if number % 2 == 0 && number > 2 => false,
        _ => (2..n).all(|i| n % i != 0) // Returns true if all the elements in 2..n cannot be divided by i
    }
}

Alexander Y

unixander

2 months ago

2.99ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    match n {
        0 | 1 => false,
        2 => true,
        _ => (2..=n/2).all(|i| n % i != 0)
    }
}

Philippe Massicotte

PMassicotte

2 months ago

3.25ms

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 sqrt_n = (n as f32).sqrt() as u32;
    for i in (3..=sqrt_n).step_by(2) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

Harsh Ranjan

harshRn

2 months ago

3.71ms

86.76kb

pub fn is_prime(n: u32) -> bool {
    println!("{n}");
    // Implement your code here
    if n == 1 { return false;}
    if n <= 3 {return true;}
    let mut c = 2;
    for i in 2..=(n/2) as u32 {
        if n % i == 0 {
            c += 1;
        }
    }
    c == 2
}

jeroenvgestel

2 months ago

3.51ms

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 upperLimit = (n as f32).sqrt() as u32;
    for i in 3..=upperLimit {
        if n % i == 0 {
            return false;
        }
    }
    true
    
}

Coppez

2 months ago

3.13ms

81.43kb

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

Coppez

2 months ago

2.94ms

81.43kb

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

Luigi Terrone

LuigiTer

2 months ago

3.73ms

81.43kb

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

Enes

enesscevik

2 months ago

2.98ms

81.43kb

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

ikatlinsky

2 months ago

2.93ms

81.43kb

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

Aztra Corporation Inc.

AZTRA2022

2 months ago

3.05ms

81.43kb

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

LeonardoPinheiro23

2 months ago

3.09ms

81.43kb

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

annececiledunand

2 months ago

2.96ms

81.43kb

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

sjmellor

3 months ago

2.90ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        0 | 1 => false,
        2 => true,
        _ if n % 2 == 0 => false,
        _ => {
            for i in (3u32..).step_by(2).take_while(|x| (x * x) <= n) {
                if n % i == 0 {
                    return false
                }
            }
            true
        }
    }
}

ggnne

3 months ago

3.17ms

81.43kb

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

Tommytto

3 months ago

2.73ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {
        return false;
    }
    if n == 2 {
        return true;
    }
    if n % 2 == 0 {
        return false;
    }
    let start = 3;
    let end = (n as f32).sqrt() as u32;
    for num in start..end+1 {
        if n % num == 0 {
            return false;
        }
    }
    return true
}

Viktor Merkurev

fennr

3 months ago

4.11ms

81.43kb

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

Anatma2

3 months ago

4.16ms

81.43kb

pub fn is_prime(n: u32) -> bool {
if n < 2 {return false}
let start = 2;
let mut end = n / 2;
    for idx in start..=end
    {
        if n % idx == 0{return false}
    }
    true
}

Anatma2

3 months ago

3.95ms

81.43kb

pub fn is_prime(n: u32) -> bool {
if n == 2 {return true}
if n < 2 {return false}
let start = 2;
let mut end = n / 2;
    for idx in start..=end
    {
        if n % idx == 0{return false}
    }
    true
}

Enriko

rix71

3 months 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

3 months 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

4 months 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

4 months 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
}