Remove Element

Given an array and a value, remove all instances of that value in place and return the new length.

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

Solution

Use two pointers.

Code

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