Problem:
Score : 500 points

Problem Statement

Given are two strings s and t consisting of lowercase English letters. Determine if there exists an integer i satisfying the following condition, and find the minimum such i if it exists.

Let s' be the concatenation of 10^{100} copies of s. t is a subsequence of the string {s'}_1{s'}_2\ldots{s'}_i (the first i characters in s').

Notes

A subsequence of a string a is a string obtained by deleting zero or more characters from a and concatenating the remaining characters without changing the relative order. For example, the subsequences of contest include net, c, and contest.

Constraints

1 \leq |s| \leq 10^5

1 \leq |t| \leq 10^5

s and t consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

s
t

Output

If there exists an integer i satisfying the following condition, print the minimum such i; otherwise, print -1.

Sample Input 1

contest
son

Sample Output 1

10

t = son is a subsequence of the string contestcon (the first 10 characters in s' = contestcontestcontest...), so i = 10 satisfies the condition.

On the other hand, t is not a subsequence of the string contestco (the first 9 characters in s'), so i = 9 does not satisfy the condition.

Similarly, any integer less than 9 does not satisfy the condition, either. Thus, the minimum integer i satisfying the condition is 10.

Sample Input 2

contest
programming

Sample Output 2

-1

t = programming is not a substring of s' = contestcontestcontest.... Thus, there is no integer i satisfying the condition.

Sample Input 3

contest
sentence

Sample Output 3

33

Note that the answer may not fit into a 32-bit integer type, though we cannot put such a case here.

Solution in C++14 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <algorithm>
#include <map>
#include <iomanip>

using namespace std;

int main(){
    
    string S, T; cin >> S >> T;

    bool flag = true;

    map <char, int> Smap;
    vector < vector<int> > Schar(26);
    for (int i = 0; i < S.length(); i++){
        Smap[S[i]] ++;
        Schar[S[i] - 'a'].push_back(i + 1);
    }
    for (int i = 0; i < T.length(); i++){
        if (Smap[T[i]] == 0){
            flag = false;
            break;
        }
    }
    
    if (flag == true){
        long long ans = 0, cnt = 0;
        int Slong = S.length();
        for (int i = 0; i < T.length(); i++){
            int Tchar = T[i] - 'a';
            
            for (int j = 0; j < Schar[Tchar].size(); j++){
                if (ans < cnt * Slong + Schar[Tchar][j]){
                    ans = cnt * Slong + Schar[Tchar][j];
                    break;
                }else if(j == Schar[Tchar].size() - 1){
                    cnt++;
                    ans = cnt * Slong + Schar[Tchar][0];
                }
            }
        }
        cout << ans << endl;
    }else{
        cout << -1 << endl;
    }

    return 0;
}