[CTCI] 最长合成字符串

 1 class LongestString {
 2 public:
 3     bool canBuild(string &s, bool isOriginalWord, map<string, bool> &mp) {
 4         if (mp.find(s) != mp.end() && !isOriginalWord) return mp[s];
 5         for (int i = 1; i < s.length(); ++i) {
 6             string left = s.substr(0, i);
 7             string right = s.substr(i);
 8             if (mp.find(left) != mp.end() && mp[left] && canBuild(right, false, mp)) {
 9                 return true;
10             }
11         }
12         mp[s] = false;
13         return false;
14     }
15     int getLongest(vector<string> str, int n) {
16         // write code here
17         map<string, bool> mp;
18         for (auto &s : str) mp[s] = true;
19         sort(str.begin(), str.end(), [](const string &a, const string &b) {
20             return a.length() > b.length();
21         });
22         for (auto &s : str) {
23             if (canBuild(s, true, mp)) return s.length();
24         }
25         return 0;
26     }
27 };