hihocoder1829 Tomb Raider

思路：

暴力枚举。

实现：

#include <iostream>
#include <set>
#include <vector>
using namespace std;

void get_subseq(string s, string x, int cur, set<string>& st)
{
    if (cur == s.length()) { if (x != "") st.insert(x); return; }
    get_subseq(s, x + s[cur], cur + 1, st);
    get_subseq(s, x, cur + 1, st);
}

bool is_subseq(string s, string t)
{
    int i = 0, j = 0;
    while (i < s.length() && j < t.length())
    {
        if (t[j] != s[i]) j++;
        else i++;
    }
    return i == s.length();
}

bool check(string s, vector<string> v)
{
    for (int i = 1; i < v.size(); i++)
    {
        bool flg = false;
        int l = v[i].length();
        for (int j = 0; j < l; j++)
        {
            string tmp = v[i].substr(j, l - j) + v[i].substr(0, j);
            if (is_subseq(s, tmp)) { flg = true; break; }
        }
        if (!flg) return false;
    }
    return true;
}

int main()
{
    int n;
    string s;
    while (cin >> n)
    {
        vector<string> v;
        for (int i = 0; i < n; i++) { cin >> s; v.push_back(s); }
        set<string> st;
        vector<string> buf;
        get_subseq(v[0], "", 0, st);
        for (auto it: st)
        {
            int l = it.length();
            for (int i = 1; i < l; i++)
            {
                string tmp = it.substr(i, l - i) + it.substr(0, i);
                buf.push_back(tmp);
            }
        }
        for (auto it: buf) st.insert(it);
        int maxn = 0; string ans = "zzzzzzzzzz";
        for (auto it: st)
        {
            if (check(it, v) && (it.length() > maxn || (it.length() == maxn && it < ans)))
            {
                ans = it;
                maxn = it.length();
            }
        }
        if (ans == "zzzzzzzzzz") cout << 0 << endl;
        else cout << ans << endl;
    }
    return 0;
}