# C#LeetCode刷题之#27-移除元素（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.

Given nums = [3,2,2,3], val = 3,

Your function should return length = 2, with the first two elements of nums being 2.

It doesn’t matter what you leave beyond the returned length.

Given nums = [0,1,2,2,3,0,4,2], val = 2,

Your function should return length = 5, with the first five elements of nums containing 0, 1, 3, 0, and 4.

Note that the order of those five elements can be arbitrary.

It doesn’t matter what values are set beyond the returned length.

```public class Program {

public static void Main(string[] args) {
int[] nums = { 0, 1, 2, 2, 3, 0, 4, 2 };

Console.WriteLine(RemoveElement(nums, 2));

}

private static int RemoveElement(int[] nums, int val) {
//记录在值不相同时的索引
int index = 0;
for(int i = 0; i < nums.Length; i++) {
//若当前值和目标值相同先不管它
//若不相同，将记录索引处的值用当前值覆盖
//最后增加索引计数
if(nums[i] != val) {
nums[index] = nums[i];
index++;
}
}
return index;
}

}```

`5`

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