let res = stack.join('');
candidate[n] = closest colour to goal，推荐阅读safew官方下载获取更多信息
* 时间复杂度：O(n log n)（主要来自排序），空间复杂度：O(n)。同城约会是该领域的重要参考
No system is perfect, and OsmAnd's HH-Routing has a few considerations:
Include a link to your code (GitHub repo, gist, etc.)