Mutable Slices

In this challenge, you'll explore how to work with mutable slices in Rust. A mutable slice, &mut [T], allows you to modify the elements of a collection directly and efficiently without creating a new collection.

Slices are a fundamental part of Rust, providing a view into contiguous sequences of elements such as arrays or vectors. When working with slices, you can iterate over and manipulate the elements dynamically.

Your Task

Write a function modify_elements(slice: &mut [i32]) that modifies the elements of a mutable slice of integers in the following way:

Double each even number in the slice.
Subtract 1 from each odd number in the slice.
Modify the elements directly without creating a new collection.

Example

let mut numbers = [1, 2, 3, 4, 5];
modify_elements(&mut numbers);
 
// Odd numbers reduced by 1
// Even numbers doubled
assert_eq!(numbers, [0, 4, 2, 8, 4]);
 
let mut numbers = [10, 15, 20];
modify_elements(&mut numbers);
 
// 10 -> 20, 15 -> 14, 20 -> 40
assert_eq!(numbers, [20, 14, 40]);

Hints

If you're stuck, here are some hints to help you:

Additional Hints

Use the .iter_mut() method to traverse the slice by mutable reference.
Remember that you can check if a number is even using num % 2 == 0.
Use dereferencing (*) to update the value pointed to by the mutable reference.
You can use a for loop with mutable references for concise modification.
The slice directly modifies the original collection it is derived from, so no need to return anything.

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Solutions

Leo

leyonh

8 hours ago

4.14ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for (i, v) in slice.iter_mut().enumerate() {
        if *v % 2 == 0 {
            *v *= 2;
        }else{
            *v -= 1;
        }
    }
}

Leo

leyonh

8 hours ago

4.39ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for (i, v) in slice.iter_mut().enumerate() {
        if *v % 2 == 0 {
            *v *= 2;
        }else{
            *v -= 1;
        }
    }
}

uniquefan

10 hours ago

5.04ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for item in slice.iter_mut() {
        if *item % 2 == 0{
            *item *=2;
        }
        else{
            *item -=1;
        }
    }
}

Augsorn Chanklad

up2code

a day ago

4.18ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for s in slice.iter_mut() {
        if *s % 2 == 0 {
            *s = *s*2;
        } else {
            *s = *s-1;
        }
    }
}

Tpel917

2 days ago

4.71ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for number in slice.iter_mut() {
        if *number % 2 ==0 {
            *number *=2;
        } else {
            *number -=1;
        }
    }
}

ohmurphy

3 days ago

5.60ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for elm in slice.iter_mut() {
        if *elm % 2 == 0 {
            *elm = *elm * 2;
        } else {
            *elm -= 1;
        }
    }
}

___

justcode-28

3 days ago

5.14ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for x in slice {
        if *x & 1 == 0 {
            *x *= 2 
        } else { *x -= 1}
    }
}

Alexandr

Alexandr-Gluhov

3 days ago

5.72ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements
    slice.iter_mut().for_each(|el| if *el % 2 == 0 {
        *el *= 2
    } else {
        *el -= 1
    });
}

gerald3rivii

4 days ago

6.53ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for element in slice.iter_mut(){
        if *element % 2 == 0{
            *element *= 2;
        }else{
            *element -= 1;
        }
    }
}

0x1057801

0x1057

4 days ago

5.10ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for ele in slice {
        if *ele % 2 == 0 {
            *ele *= 2;
        }
        if *ele % 2 != 0 {
            *ele -= 1;
        }
    }
}

Stas

nevmstas

5 days ago

5.68ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for num in slice {
        if *num % 2 == 0 {
            *num = *num * 2;
        } else {
            *num = *num - 1;
        }
    }
}

Tommy

verse215

7 days ago

5.39ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for i in slice {
        if *i % 2 == 0 {
            *i = *i * 2;
        } else {
            *i = *i - 1;
        }
    }
}

J. Sassen

JSG-GIT

7 days ago

6.75ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num%2==0 { *num*=2; }
        else { *num-=1; }
    }
}

Tristan Young

DragonBeast829

7 days ago

4.46ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for x in slice.iter_mut() {
        if *x % 2 == 0 {
            *x *= 2
        } else {
            *x -= 1
        }
    }
}

msned

7 days ago

5.10ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for item in slice.iter_mut(){
        if *item % 2 == 0{
            *item *= 2;
        } else{
            *item -= 1;
        }
    }
}

Teimur Gasanov

teimurjan

7 days ago

6.13ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for elem in slice.iter_mut() {
        if *elem % 2 == 0 {
            *elem *= 2;
        } else {
            *elem -= 1
        }
    }
}

Seth Wood

seth-wood

8 days ago

4.94ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2
        } else {
            *num -= 1
        }
    }
}

AlphaN00mer1cal

8 days ago

6.08ms

89.23kb


pub fn transform_even_odd(slice: &mut [i32]) {
   for val in slice.iter_mut(){
        if *val % 2 == 0 {
            *val *= 2;
        }
        else{
            *val -= 1;
        }
   }
}

Kanak Shilledar

kanakshilledar

8 days ago

4.75ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for ele in slice.iter_mut() {
        if *ele % 2 == 0 {
            *ele *= 2;
        } else {
            *ele -= 1
        }
    }
}

Halloweedev

8 days ago

4.11ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        }
        else {
            *num -= 1;
        }        
    }   
}

Octavian

orouwk

9 days ago

5.07ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for e in slice.iter_mut() {
        if *e%2==0 { 
            *e*=2
        } else {
            *e-=1
        }
    }
}

Envoid

Envo1d

9 days ago

5.46ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    slice.iter_mut().for_each(|v|{
        if *v %2 == 0 {
            *v *= 2;
        } else {
            *v -= 1;
        }
    })
}

Envoid

Envo1d

9 days ago

6.47ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    slice.iter_mut().for_each(|v|{
        if *v %2 == 0 {
            *v *= 2;
        } else {
            *v -= 1;
        }
    })
}

Gurneet singh

GS-Jatt

10 days ago

4.78ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    slice.iter_mut().for_each(|e|{
        if *e%2 == 0 {
            *e *= 2;
        }else{
            *e-= 1;
        }
    })
}

zazapalm3012

11 days ago

4.09ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for i in 0..slice.len(){
        if slice[i] % 2 == 0{
            slice[i] = slice[i]+slice[i];
        }
        else{
            slice[i]-=1;
        }
    }
}

zazapalm3012

11 days ago

4.97ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for i in 0..slice.len(){
        if slice[i] % 2 == 0{
            slice[i] = slice[i]+slice[i];
        }
        else{
            slice[i]-=1;
        }
    }
}

至尊宝

shankun

11 days ago

5.36ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for i in slice.iter_mut() {
        if *i % 2 == 0 {
            *i *= 2; // 偶数乘以2
        } else {
            *i -= 1; // 奇数减去1
        }
    }
}

4itech-micky

11 days ago

4.96ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2
        } else {
            *num -= 1
        }
    }
}

LLukeDB

12 days ago

45.15ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num = *num * 2;
        }
        else {
            *num = *num - 1;
        }
    }
}

AymericRT

13 days ago

4.91ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for i in slice.iter_mut(){
        if *i%2 == 0{
            *i = *i * 2;
        }else{
            *i = *i -1;
        }
    }
}

JesAlbLop

JesAlblop

13 days ago

4.90ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

hex-order

idan-KH

13 days ago

10.04ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

hex-order

idan-KH

13 days ago

5.02ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

Health-Care-Movie

13 days ago

5.51ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    slice.iter_mut().for_each(|x| {
        match *x % 2 {
            0 => *x *= 2,
            _ => *x -= 1,
        }
    })
}

Thomastienn

14 days ago

9.64ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

Splatrac

splatrac

14 days ago

6.01ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for i in slice.iter_mut() {
        if *i % 2 == 0 {
            *i = *i*2;
        } else {
            *i = *i - 1;
        }
    }
    ()
}

Nicolas Zamarreno

nzamarreno

15 days ago

5.86ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for element in slice.iter_mut() {
        if *element % 2 == 0 {
            *element = *element * 2;
        } else {
            *element = *element - 1;
        }
    }
}

wertion555

15 days ago

5.78ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for i in slice.iter_mut(){
        if *i % 2 == 0{
            *i = *i * 2;
        }else{
            *i = *i - 1;
        }
    }
}

Ismail Rohaga

ismailrohaga

16 days ago

5.84ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

Ismail Rohaga

ismailrohaga

16 days ago

5.83ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

Ismail Rohaga

ismailrohaga

16 days ago

4.53ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

Trịnh Chấn Duy

Duyyy123

17 days ago

4.51ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    slice.iter_mut().for_each(|x| {
        if *x % 2 == 0 {
            *x *= 2; // Double the even numbers
        } else {
            *x -= 1; // Reduce the odd numbers
        }
    });
}

Sai Ranjit Tummalapalli

sairanjit

19 days ago

5.28ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

Najib-Kassab

19 days ago

5.32ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for elements in 0..slice.len(){
        if slice[elements] %2 ==0{
            slice[elements] *=2;
        }
        else{
            slice[elements] -=1;
        }
    }
}

Liyqq

19 days ago

4.07ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    let transform_fn = |num: &mut i32| 
                    if *num % 2 == 0 { *num = *num*2 } 
                    else { *num = *num-1 };
    slice.iter_mut().for_each(transform_fn);
}

cyberspace lee

cyberspacelee

21 days ago

4.17ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    slice.iter_mut().for_each(|x| {
        if *x % 2 == 0 {
            *x = *x * 2;
        } else {
            *x = *x - 1;
        }
    });
    
}

Ryosuke Kida

ryskit

22 days ago

4.52ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for x in slice.iter_mut() {
        if *x % 2 == 0 {
            *x = *x * 2;
        } else {
            *x = *x - 1;
        }
    }
}

Stanluigi Saint-Ruste

CallMeLuigiv2

23 days ago

4.39ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
   
   for i in 0..slice.len(){
    if slice[i] % 2 == 0{
        slice[i] *=2
    }
    else{
        slice[i] -=1;
    }
   }
}

Nicolai

Posmac

23 days ago

6.70ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}

Nicolai

Posmac

23 days ago

4.50ms

89.23kb

pub fn transform_even_odd(slice: &mut [i32]) {
    // Your code here: iterate over the mutable slice and modify its elements.
    for num in slice.iter_mut() {
        if *num % 2 == 0 {
            *num *= 2;
        } else {
            *num -= 1;
        }
    }
}