## 27. Remove Element

Given an array *nums* and a value `val`

, remove all instances of that value **in-place** and return the new length.

Do not allocate extra space for another array, you must do this by **modifying the input array in-place** with `O(1)`

extra memory.

The order of elements can be changed. It doesn't matter what you leave beyond the new length.

**Clarification:**

Confused why the returned value is an integer but your answer is an array?

Note that the input array is passed in by **reference**, which means a modification to the input array will be known to the caller as well.

Internally you can think of this:

//numsis passed in by reference. (i.e., without making a copy) int len = removeElement(nums, val); // any modification tonumsin your function would be known by the caller. // using the length returned by your function, it prints the firstlenelements. for (int i = 0; i < len; i++) { print(nums[i]); }

**Example 1:**

Input:nums = [3,2,2,3], val = 3Output:2, nums = [2,2]Explanation:Your function should return length =2, with the first two elements ofnumsbeing2. It doesn't matter what you leave beyond the returned length. For example if you return 2 with nums = [2,2,3,3] or nums = [2,2,0,0], your answer will be accepted.

**Example 2:**

Input:nums = [0,1,2,2,3,0,4,2], val = 2Output:5, nums = [0,1,4,0,3]Explanation:Your function should return length =, with the first five elements of`5`

containing`nums`

,`0`

,`1`

,`3`

, and`0`

4. Note that the order of those five elements can be arbitrary. It doesn't matter what values are set beyond the returned length.

**Constraints:**

`0 <= nums.length <= 100`

`0 <= nums[i] <= 50`

`0 <= val <= 100`

## Rust Solution

```
struct Solution;
impl Solution {
fn remove_element(nums: &mut Vec<i32>, val: i32) -> i32 {
let n: usize = nums.len();
let mut size: usize = 0;
for i in 0..n {
if nums[i] != val {
nums[size] = nums[i];
size += 1;
}
}
size as i32
}
}
#[test]
fn test() {
let mut nums = vec![3, 2, 2, 3];
let val = 3;
assert_eq!(Solution::remove_element(&mut nums, val), 2);
let mut nums = vec![0, 1, 2, 2, 3, 0, 4, 2];
let val = 2;
assert_eq!(Solution::remove_element(&mut nums, val), 5);
}
```

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