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<bits/stdc++.h>
#define ll long long
using namespace std;
vector<int>v[27];
int main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  string s,t;
  int x;
  cin>>s>>t;
  for(int i=0;i<s.size();i++)
  {
    x=s[i]-'a';
    v[x].push_back(i+1);
  }
  int a=0,flag=0;
  ll int len=0,cy=0,sz=t.size();
  for(int i=0;i<sz;i++)
  {
    x=t[i]-'a';
    if(v[x].size()==0){cout<<"-1\n";return 0;}
   int flag=1,zz=v[x].size();
    for(int j=0;j<zz;j++)
    {
      if(v[x][j]>len){ len=v[x][j];flag=0;break;}
    }
    if(flag==1){cy++;len=v[x][0];}
  }

  cout<<s.size()*cy+len<<"\n";
  return 0;

}