23. 删除排序数组中的重复项

<?php
class Solution {
    public function removeDuplicates(&$nums) {
        if (!$nums) return 0;
        $i = 0;
        for ($j = 1; $j < count($nums); $j++) {
            if ($nums[$j] != $nums[$i]) {
                $i++;
                $nums[$i] = $nums[$j];
            }
        }
        return $i + 1;
    }
}
$nums = [1,1,3,3,5,6,7,7];
$cls = new Solution();
$r = $cls->removeDuplicates($nums);
echo $r;