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: Runtime Error)

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
    int i;
    array<bool, 28> exist{};
    char s[1000001];
    char t[1000001];
    scanf("%s%s", s, t);
    ll sLen=strlen(s);
    ll tLen=strlen(t);
    for(i=0; i<sLen; i++){
        exist[s[i]-'a']=true;
    }
    bool can=true;
    char *actualS=s, *nextS;
    ll rounds=0;
    for(i=0; i<tLen && can; i++){
        nextS=strchr(actualS, t[i]);
        if(nextS==NULL){
            nextS=strchr(s, t[i]);
            rounds++;
        }
        actualS=nextS+1;
    }
    if(can){
        cout << (sLen*rounds)+actualS-s << "\n";
    }
    else{
        printf("-1");
    }
}