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 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
#define llinf 4154118101919364364

int main(void){
  long long i,j,narr[524288][32],sl,tl,mem[32],r=0,k;
  char s[524288],t[524288];
  scanf("%s%s",&s[1],&t[1]);
  sl=strlen(&s[1]);
  for(i=1;i<=sl;i++){
    s[sl+i]=s[i];
  }
  s[2*sl+1]=0;
  tl=strlen(&t[1]);
  for(i=0;i<32;i++){mem[i]=llinf;}
  for(i=2*sl;i>=0;i--){
    for(j=0;j<32;j++){
      narr[i][j]=mem[j];
    }
    mem[s[i]-'a']=i;
  }
  for(i=1;i<=tl;i++){
    if(narr[r%sl][t[i]-'a']==llinf){
      printf("-1\n");
      return 0;
    }
    k=narr[r%sl][t[i]-'a'];
    r-=(r%sl);
    r+=k;
  }
  printf("%lld\n",r);
  return 0;
}