具体解释看这篇：https://leetcode-cn.com/problems/number-of-provinces/solution/jie-zhe-ge-wen-ti-ke-pu-yi-xia-bing-cha-0unne/ 相关文章： 2022-12-23 2021-11-12 2022-01-07 2022-01-15 2021-11-20 2021-10-27 2021-11-20