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:
// nums is passed in by reference. (i.e., without making a copy) int len = removeElement(nums, val); // any modification to nums in your function would be known by the caller. // using the length returned by your function, it prints the first len elements. for (int i = 0; i < len; i++) { print(nums[i]); }
Example 1:
Input: nums = [3,2,2,3], val = 3 Output: 2, nums = [2,2] Explanation: 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. 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 = 2 Output: 5, nums = [0,1,4,0,3] Explanation: Your function should return length =5
, with the first five elements ofnums
containing0
,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.
Constraints:
0 <= nums.length <= 100
0 <= nums[i] <= 50
0 <= val <= 100
class Solution:
def removeElement(self, nums: List[int], val: int) -> int:
cnt, n = 0, len(nums)
for i in range(n):
if nums[i] == val:
cnt += 1
else:
nums[i - cnt] = nums[i]
return n - cnt
class Solution {
public int removeElement(int[] nums, int val) {
int cnt = 0, n = nums.length;
for (int i = 0; i < n; ++i) {
if (nums[i] == val) ++cnt;
else nums[i - cnt] = nums[i];
}
return n - cnt;
}
}
class Solution {
public:
int removeElement(vector<int>& nums, int val) {
int cnt = 0, n = nums.size();
for (int i = 0; i < n; ++i) {
if (nums[i] == val) ++cnt;
else nums[i - cnt] = nums[i];
}
return n - cnt;
}
};
/**
* @param {number[]} nums
* @param {number} val
* @return {number}
*/
var removeElement = function (nums, val) {
let cnt = 0;
const n = nums.length;
for (let i = 0; i < n; ++i) {
if (nums[i] == val) ++cnt;
else nums[i - cnt] = nums[i];
}
return n - cnt;
};
func removeElement(nums []int, val int) int {
cnt, n := 0, len(nums)
for i := 0; i < n; i++ {
if (nums[i] == val) {
cnt++
} else {
nums[i - cnt] = nums[i]
}
}
return n - cnt
}
impl Solution {
pub fn remove_element(nums: &mut Vec<i32>, val: i32) -> i32 {
let mut len = 0;
for i in 0..nums.len() {
if nums[i] != val {
nums[len] = nums[i];
len += 1;
}
}
len as i32
}
}