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

Christopher Nielson

c-nielson

3 days ago

3.23ms

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

Christopher Nielson

c-nielson

3 days ago

3.81ms

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

Christopher Nielson

c-nielson

3 days ago

3.07ms

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 root: f64 = (n as f64).sqrt();
        let mut divisors = (3..=root as u32).step_by(2).into_iter();
        divisors.all(|d| n % d != 0)
    }
}

SeinPierre

4 days ago

2.95ms

81.43kb

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

Elliott Draper

ejdraper

7 days ago

2.85ms

86.82kb

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

0xMushow

7 days ago

3.21ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Handle edge cases
    if n < 2 {
        return false;
    }
    if n == 2 {
        return true;
    }
    if n % 2 == 0 {
        return false;
    }
    // Check divisibility from 3 up to the square root of n
    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
}

Whisper_icoma

1378046967

7 days ago

3.27ms

81.43kb

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

エヴァンゲリオン

Lu-zihang

10 days ago

5.30ms

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
}

Florian Gaudin-Delrieu

FlorianGD

12 days ago

2.94ms

86.80kb

pub fn is_prime(n: u32) -> bool {
    let n = n as usize;
    let mut primes: Vec<bool> = vec![true; n +1];
    primes[0] = false;
    primes[1] = false;
    for i in 2..=n {
        if primes[i] {
            for j in ((i*i)..=n).step_by(i) {
                primes[j] = false;
            }
        }
    }
    primes[n]
}

Sthitaprajna Sahu

sthitasahu

13 days ago

3.31ms

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
}

Takuro Niitsuma

otakumesi

13 days ago

3.73ms

85.89kb

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

dawwestk

14 days ago

3.25ms

81.43kb

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

PangoSea

kapaseker

16 days ago

6.25ms

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

Sakura

sakkura

20 days ago

4.23ms

81.43kb

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

Tengz Mao

MaoX-Yu

20 days ago

6.46ms

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;
        }
    }
    true
}

Ahmet Özcan

ahmetoozcan

21 days ago

3.36ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    match n {
        0 | 1 => false,
        2 | 3 => true,
        _ if n % 2 == 0 || n % 3 == 0 => false,
        _ => {
            let mut i = 5;
            while i * i <= n {
                if n % i == 0 || n % (i + 2) == 0 {
                    return false;
                }
                i += 6;
            }
            true
        }
    }
}

mm-yyyy

21 days ago

2.96ms

81.43kb

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

Bugra Okumus

bgraokmush

21 days ago

2.83ms

81.43kb

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

Dominicm99

21 days ago

3.19ms

81.43kb

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

Mikhail Shutov

mshutov

22 days ago

3.09ms

81.43kb

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

vikingNR

22 days ago

3.98ms

81.43kb

pub fn is_prime(n: u32) -> bool{
    if n < 2 {return false}
    if n == 2 || n == 3 {return true}
    if n % 2 == 0 || n % 3 == 0 {return false}
    for i in (5..=(n as f32).sqrt() as u32).step_by(6){
        if n % i == 0 || n % (i + 2) == 0 {return false}
    }
    return true
    // Implement your code here
}

Ohayo

labike

22 days ago

3.04ms

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

rawar089

23 days ago

2.78ms

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

Infinite Time

InfiniteTime3000

23 days ago

5.92ms

86.76kb

pub fn is_prime(n: u32) -> bool {
    println!("{}", n);
    if n == 2 {return true;}
    if n>2 {
        if n%2 == 0 {
            return false;
        } else {
            for i in 3..=(f64::from(n).sqrt() as u32 + 1) {
                if n%i != 0 {
                    continue
                } else {
                    return false;
                }
            }
            return true;
        }
    } else {
        return false;
    }
}

matsuyama-k1

23 days ago

5.62ms

81.43kb

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

PavelPerna

24 days ago

3.12ms

86.75kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    let primes :Vec<u32> = vec![2,3,5,7,11,13,17,23,29,31,37,41];
    match n {
        ..=1 => false,
        ..=3 => true,
        _ => {
                let mut r = true;
                for i in primes {
                    if (i < n) && (n % i == 0){
                        r = false;
                    }
                }
                r
            }
    }
  }

Vlad

mvldmihai

24 days ago

3.83ms

81.43kb

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

Stan

i2z4

24 days ago

3.15ms

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
}

zahrajavar

a month ago

4.75ms

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

goerfra

a month ago

11.82ms

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 f32).sqrt() as u32 + 1) {
        if n % i == 0 {
            return false;
        }
    }
    return true;
}

L-Super

a month ago

3.15ms

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 number in 2..n {
        if n % number == 0 {
            return false;
        }
    }
    true
}

L-Super

a month ago

3.26ms

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;
    }
    for number in 2..n {
        if n % number == 0 {
            return false;
        }
    }
    true
}

karapy

a month ago

3.26ms

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
}

hubbardip

a month ago

3.30ms

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..(f32::sqrt(n as f32) as u32 + 1) {
        if n % i == 0 {
            return false;
        }
    }
    true
}

facat

a month ago

3.35ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // Implement your code here
    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
}

Yofifi

a month ago

3.14ms

81.43kb

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

Yofifi

a month ago

3.01ms

81.43kb

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

Larry Oates

Leafmun-certii

a month ago

3.87ms

81.43kb

pub fn is_prime(n: u32) -> bool {
    // numbers less that 2 aren't prime
    if n < 2 {
        return false
    }
    // Even numbers
    if n % 2 == 0 {
        if n == 2 {
            return true
        }
        else {
            return false
        }
    }
    // Check odd numbers
    let sqrt = (n as f64).sqrt() as u32;
    for x in (3..=sqrt).step_by(2) {
        if n % x == 0 {
            return false
        }
    }
    true
}

aey4

a month ago

2.79ms

81.43kb

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

Tarokc

a month ago

3.61ms

81.43kb

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

viky

vikyw89

a month ago

3.04ms

81.43kb

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

Caio César

caiocdcs

a month 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;
    }
    let up = (n as f64).sqrt() as u32;
    for i in 3..=up {
        if n % i == 0 {
            return false;
        }
    }
    true
}

nedrw

a month ago

3.80ms

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 3..n/2 {
            if n % i == 0 { return false; }
        }
    }
    true
}

RonaldoArayadev

a month ago

3.29ms

81.43kb

use std::num;
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 up = (n as f64).sqrt() as u32;
    for i in 3..=up {
        if n % i == 0 {return false;}
    }
    return true;
}

Sir Woody Hackswell

Hackswell

a month ago

3.69ms

81.43kb

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

Sir Woody Hackswell

Hackswell

a month ago

3.58ms

81.43kb

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

Yamami

Yamami1221

a month ago

3.13ms

81.43kb

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

JeppeFoldberg

a month ago

2.98ms

81.43kb

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

chuyuanlinzi

a month ago

3.10ms

81.43kb

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

doroshtapgh

a month ago

3.11ms

81.43kb

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