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: Wrong Answer)

#include <iostream>
#include <string>
#include <vector>
#include <map>

using namespace std;

string tre;

bool moze(int n, string k){
    int j = 0;
   for (int i=0; i < n && j < k.length(); i++) 
       if (k[j] == tre[i]) 
         j++; 
  
   return (j==k.length()); 
}

int main() {
  string t;
  cin >> tre >> t;
  map <char, bool> ima;
  for (int i = 0; i < tre.length(); i++) 
   ima[tre[i]] = true;
  for (int i = 0; i < t.length(); i++)
    if (!ima[t[i]]){
      cout << "-1";
      return 0;
    }
  int l = 1, r = 10000000;
  while (tre.size() < 10000000) tre += tre;
  while (l < r){
    int mid = (l+r)/2;
    if (!moze(mid,t)) l = mid + 1;
    else r = mid;
  }
  cout << l;
}