LeetCode 27. Remove Element

LeetCode 27. Remove Element

Description

Given an array and a value, 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.

class Solution {    public int removeElement(int[] nums, int val) {        int i = 0;        for (int j = 0; j < nums.length; j++) {            if (nums[j] != val) {                nums[i++] = nums[j];            }        }        return i;    }}

Complexity analysis

Time complexity : O(n). Assume the array has a total of n elements, both i and j traverse at most 2n steps.

Space complexity : O(1).