从2D列表中删除重复的后续条目

def remove_duplicates(matrix):
    seen = set()
    result = []
    for row in matrix:
        unique_row = []
        for item in row:
            if item not in seen:
                unique_row.append(item)
                seen.add(item)
        result.append(unique_row)
    return result

# 示例用法
matrix = [[1, 2, 3], [4, 5, 6], [1, 2, 3], [7, 8, 9]]
result = remove_duplicates(matrix)
print(result)
# 输出: [[1, 2, 3], [4, 5, 6], [], [7, 8, 9]]