https://111qqz.com/en/tags/dfs%E5%BA%8F/Recent content in Dfs序 on 111qqz's blogHugo -- gohugo.ioen© 2015-2026 111qqzFri, 14 Aug 2015 19:50:00 +0000https://111qqz.com/en/post/acm-icpc/2015/2015-08-14-codeforces570d-treerequestsdfse5ba8f/Fri, 14 Aug 2015 19:50:00 +0000https://111qqz.com/en/post/acm-icpc/2015/2015-08-14-codeforces570d-treerequestsdfse5ba8f/<p>因为字母的排列顺序是任意的,所以判断能否形成回文串的条件就成了出现次数为奇数的字母的个数是否大于1个,如果是,那么一定不能形成回文串,否则一定可以.</p>