💡 LeetCode 27 - Remove Element

문제

Given an integer array nums and an integer val, remove all occurrences of val in nums in-place. The order of the elements may be changed. Then return the number of elements in nums which are not equal to val.
Consider the number of elements in nums which are not equal to val be k, to get accepted, you need to do the following things:

Change the array nums such that the first k elements of nums contain the elements which are not equal to val. The remaining elements of nums are not important as well as the size of nums. Return k.
Custom Judge:

The judge will test your solution with the following code:
```java int[] nums = […]; // Input array int val = …; // Value to remove int[] expectedNums = […]; // The expected answer with correct length. // It is sorted with no values equaling val.

int k = removeElement(nums, val); // Calls your implementation

assert k == expectedNums.length; sort(nums, 0, k); // Sort the first k elements of nums for (int i = 0; i < actualLength; i++) { assert nums[i] == expectedNums[i]; }​

> If all assertions pass, then your solution will be accepted.


### 입출력 예제
#### ✅ 예제 1
```bash
Input: nums = [3,2,2,3], val = 3
Output: 2, nums = [2,2,_,_]
Explanation: Your function should return k = 2, with the first two elements of nums being 2. It does not matter what you leave beyond the returned k (hence they are underscores).​

✅ 예제 2

Input: nums = [0,1,2,2,3,0,4,2], val = 2
Output: 5, nums = [0,1,4,0,3,_,_,_]
Explanation: Your function should return k = 5, with the first five elements of nums containing 0, 0, 1, 3, and 4. Note that the five elements can be returned in any order. It does not matter what you leave beyond the returned k (hence they are underscores).​

제약조건

• 0 <= nums.length <= 100
• 0 <= nums[i] <= 50
• 0 <= val <= 100

작성 코드

class Solution {
	public int removeElement(int[] nums, int val) {
		// 1. 변수 선언 및 초기화
		int idx = 0;
		
		// 2. 순회하며 조건에 해당할 경우 배열에 대입
		for (int num : nums) {
			if (num != val) nums[idx++] = num;
		}
		
		// 3. 반환
		return idx;
	}
}