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.

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Solutions

And1

and1

a day ago

2.89ms

81.43kb

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

And1

and1

a day ago

3.01ms

81.43kb

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

And1

and1

a day ago

3.56ms

81.43kb

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

michdorf

a day ago

4.12ms

81.43kb

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

Javier Garcia

javigar322

a day ago

3.68ms

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
}

Giuliano

GiulianoCTRL

a day ago

2.96ms

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
}

mgreve

2 days ago

3.47ms

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;
        } 
        if i*i >= n {
            break;
        }
    }
    true
}

Shoma Kobayashi

kobapi28

3 days ago

3.16ms

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;
}

Dan Callaghan

danc86

3 days ago

3.02ms

81.43kb

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

Len Remmerswaal

LenRemmerswaal

3 days ago

15.39ms

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 div = 3;
    while div*div <= n {
        if n % div == 0 { return false; } // No prime
        div += 2;
    }
    true
}

Galen Seilis

galenseilis

3 days ago

3.13ms

81.43kb

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

Thitiworada

Kobeieii

4 days ago

2.96ms

81.43kb

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

Jaden Wijata

xenonminer

4 days ago

3.10ms

81.43kb

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

Kenneth Love

kennethlove

4 days ago

2.77ms

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 upper_limit: u32 = (n as f32).sqrt() as u32 + 1;
    for m in 3..upper_limit {
        if n % m == 0 { return false; } 
    }
    true
}

kylenoteboom

4 days ago

3.42ms

85.89kb

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 square_root = (n as f64).sqrt().floor() as u32;
    for x in 3..=square_root {
        if x == n { continue; }
        if n % x == 0 { 
            return false;
        }
    }
    true
}

martin-unit

5 days ago

3.00ms

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 f64).sqrt().ceil() as u32) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

Jim Lawton

jimlawton

5 days ago

3.08ms

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 == 0 {
        false
    } else {
        let upper: u32 = (n as f32).sqrt() as u32 + 1;
        for i in 3..upper {
            if n % i == 0 {
                return false;
            }
        }
        true
    }
}

Esteban Soba

XtebanUy

5 days ago

2.91ms

81.43kb

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

S P

palutz

5 days ago

3.03ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        0 | 1 => false,
        2 => true,
        n if n % 2 == 0 => false,
        _ => !(3..=(n as f64).sqrt().ceil() as u32).step_by(2).any(|d| n % d == 0),
    }
}

S P

palutz

5 days ago

2.92ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    if n < 2 {
        return false;
    }
    let ni = match i32::try_from(n) {
                Ok(nn) => nn,
                Err(_) => return false,
    };
    for i in 2..((ni/2)+1) {
        if (ni % (i as i32)) == 0 {
            return false
        } 
    }
    true
}

Markus Bergkvist

mbergkvist

5 days ago

2.82ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        0 | 1 => false,
        2 => true,
        n if n % 2 == 0 => false,
        _ => !(3..=(n as f64).sqrt().ceil() as u32)
            .step_by(2)
            .any(|divisor| n % divisor == 0),
    }
}

Markus Bergkvist

mbergkvist

5 days ago

18.03ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    let is_divisible = || {
        let mut i: u32 = 3;
        while i.pow(2) <= n {
            if n % i == 0 {
                return false;
            }
            i += 2;
        }
        true
    };
    match n {
        0 | 1 => false,
        2 => true,
        n if n % 2 == 0 => false,
        _ => is_divisible(),
    }
}

leenalmajz

6 days ago

3.19ms

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
    } else {
        for i in 2..n {
            if n % i == 0 {
                return false
            }
        }
        return true
    }
}

xiuchiliudu

6 days ago

2.94ms

81.43kb

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

Ando “Thor” Nando

DivineGod

6 days ago

2.66ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        n if n < 2 => false,
        2 => true,
        n if n % 2 == 0 => false,
        n => prime_test(n),
    }
}
fn prime_test(n: u32) -> bool {
    assert!(n > 2);
    assert!(n % 2 == 1);
    (3..=(n as f64).sqrt().ceil() as u32).filter(|t| n % t == 0).count() == 0
}

mehdihmr

6 days ago

3.63ms

81.43kb

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

Andreas

StimhackSoftware

6 days ago

3.15ms

81.43kb

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

Algorab

6 days ago

2.93ms

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;
    }
    
    let mut i = 5;
    while i * i <= n {
        if n % i == 0 || n % (i + 2) == 0 {
            return false;
        }
        i += 6;
    }
    true
}

Stefan Roas

sroas

7 days ago

3.05ms

81.43kb

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

Daniel Petrov

danielmpetrov

7 days ago

3.17ms

81.43kb

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

Jan Willems

8 days ago

7.44ms

81.43kb

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

Jörg Erdmenger

joeslow

8 days ago

3.38ms

86.81kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    println!("n is {}", n);
    if n < 2 {
        false
    } else if n == 2 {
        // even numbers
        true
    } else if n % 2 == 0 {
        // odd numbers
        false
    } else {
        let sqrt = (n as f64).sqrt() as u32;
        let upper = if sqrt > 3 { sqrt } else { 3 }; // 3 is the smallest divisor we'll ever try
        !(3..=upper).step_by(2).any(|x| n != x && n % x == 0) // return false if n is cleanly divisible by divisor and divisor is not the same as number
    }
}

qiyuan711

8 days ago

3.41ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n < 2 {
        false
    } else if n == 2 {
        true
    } else if n % 2 == 0 {
        false
    } else {
        let mut res = true;
        for i in 3..=((n as f64).sqrt() as u32) {
            if n % i == 0{
                res = false;
                break
            }
        }
        res
    }
}

yoakemae

8 days ago

3.00ms

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 limit = (n as f64).sqrt() as u32 + 1;
    for i in (3..limit).step_by(2) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

Nt2311

nt2311-vn

8 days ago

3.81ms

81.43kb

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

tinthid

8 days ago

3.67ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Handle edge cases
    if n <= 1 { return false; }  // 0 and 1 are not prime
    if n <= 3 { return true; }   // 2 and 3 are prime
    if n % 2 == 0 || n % 3 == 0 { return false; }  // Handle multiples of 2 and 3
    // Check for prime using 6k ± 1 optimization
    let mut i = 5;
    while i * i <= n {
        if n % i == 0 || n % (i + 2) == 0 {
            return false;
        }
        i += 6;
    }
    
    true
}

devarajang

8 days ago

3.98ms

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;
        }
    }
    return true;
}

jon-a-miller

8 days ago

3.04ms

81.43kb

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

Philip Mercer

DV-13

8 days ago

2.92ms

81.43kb

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

Elizabeth Doughty

Thymelizabeth

9 days ago

3.61ms

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 == 0 {
        false
    } else {
        (3..=(n as f32).sqrt().ceil() as u32).all(|i| n % i != 0)
    }
}

oDqnger

10 days ago

9.86ms

81.43kb

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

Masayuki Sunahara

tamanishi

10 days ago

4.04ms

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

s.konishi

konishu

10 days ago

2.97ms

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) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

nichideropa

10 days ago

6.29ms

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,
        _ => {
            let sqrt = (n as f64).sqrt() as u32;
            for i in 3..=sqrt {
                if n % i == 0 {
                    return false;
                }
            }
            return true
        }
    }
}

Babuuu

aynugek

10 days ago

3.41ms

81.43kb

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

Jan

jeypiti

10 days ago

2.98ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    if n == 2 {return true}
    if n < 2 || n % 2 == 0 { return false }
    println!("{:?}", n);
    let sqrt = f64::from(n).sqrt() as u32;
    for i in (3..=sqrt).step_by(2) {
        if n % i == 0 { return false }
    }
    true
}

0xsmarter

11 days ago

3.53ms

81.43kb

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

Oebelus

oebelus

11 days ago

3.53ms

81.43kb

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

tsuchiya-d

tsucchinoko

11 days ago

2.81ms

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,
        _ => {
            let sqrt_n = (n as f64).sqrt() as u32;
            (3..=sqrt_n).step_by(2).all(|i| n % i != 0)
        }
    }
}

Lauri Sarap

LauriSarap

12 days ago

3.26ms

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 top = (n as f64).sqrt().round() as u32;
    for i in 3..=top {
        if is_divisible(n, i) == true {
            return false;
        }
    };
    fn is_divisible(numerator: u32, denominator: u32) -> bool {
        if numerator % denominator == 0 {
            return true;
        }
        else {
            return false;
        }
    }
    return true;
}