class Solution {
  private static int skipVal(int[] nums, int val, int i) {
    for (
    /* no-op */ ; i >= 0 && nums[i] == val; /* no-op */ ) {
      --i;
    }

    return i;
  }

  public int removeElement(int[] nums, int val) {
    var r = skipVal(nums, val, nums.length - 1);

    int l;
    for (l = 0; l < r; ++l) {
      if (nums[l] == val) {
        var tmp = nums[l];
        nums[l] = nums[r];
        nums[r] = tmp;

        r = skipVal(nums, val, r);
      }
    }

    // shift ‹l› to the first ‹val›
    while (l < nums.length && nums[l] != val) {
      ++l;
    }

    return l;
  }
}