如何合并多维数组中的重复项？

def merge_duplicates(arr):
    # 步骤1：将多维数组中的元素存储到新数组中
    new_arr = []
    for sublist in arr:
        for item in sublist:
            new_arr.append(item)
    
    # 步骤2：使用哈希表记录每个元素的出现次数
    count_map = {}
    for item in new_arr:
        if item in count_map:
            count_map[item] += 1
        else:
            count_map[item] = 1
    
    # 步骤3和4：检查重复项并删除
    merged_arr = []
    for item in new_arr:
        if count_map[item] > 1:
            count_map[item] -= 1
        else:
            merged_arr.append(item)
    
    # 步骤6：返回合并后的数组
    return merged_arr