Solution.cpp

class Solution {
public:
    string minimumString(string a, string b, string c) {
        vector<string> s = {a, b, c};
        vector<vector<int>> perm = {{0, 1, 2}, {0, 2, 1}, {1, 0, 2}, {1, 2, 0}, {2, 1, 0}, {2, 0, 1}};
        string ans = "";
        for (auto& p : perm) {
            int i = p[0], j = p[1], k = p[2];
            string t = f(f(s[i], s[j]), s[k]);
            if (ans == "" || t.size() < ans.size() || (t.size() == ans.size() && t < ans)) {
                ans = t;
            }
        }
        return ans;
    }

    string f(string s, string t) {
        if (s.find(t) != string::npos) {
            return s;
        }
        if (t.find(s) != string::npos) {
            return t;
        }
        int m = s.size(), n = t.size();
        for (int i = min(m, n); i; --i) {
            if (s.substr(m - i) == t.substr(0, i)) {
                return s + t.substr(i);
            }
        }
        return s + t;
    };
};