1、包含小写字母出现abcde为偶数的最长子串。枚举然后判断 bool JudgeStr(string s) { unordered_map<char, int> umap; for (int i = 0; i < s.size(); ++i) { if (!islower(s[i])) { return false; } else { umap[s[i]]++; } } if ((umap...