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 <bits/stdc++.h>
#define be(v) (v).begin(),(v).end()
#define pb(q) push_back(q)
#define doublecout(a) cout<<fixed<<setprecision(10)<<a<<endl;
typedef long long ll;
using namespace std;
const ll mod=1000000007,mod9=1000000009;
template <class T>inline T lcm(T a,T b){return (a*b/__gcd(a,b));}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    string s,t;
    cin>>s>>t;
    ll n=s.length();
    ll m=t.length();
    bool check[26]={0};
    for(int i=0;i<n;i++){
        check[s[i]-'a']=true;
    }
    for(int i=0;i<m;i++){
        if(check[t[i]-'a']==false){
            cout << -1<<endl;
            return 0;
        }
    }
    ll alpha[26];
    for(int i=0;i<26;i++){
        alpha[i]=-1;
    }
    ll maki[n][26];
    for(int i=n-1;i>=0;i--){
        for(int j=0;j<26;j++){
            maki[i][j]=alpha[j];
        }
        alpha[s[i]-'a']=i;
    }
    for(int i=n-1;i>=0;i--){
        for(int j=0;j<26;j++){
            maki[i][j]=alpha[j];
        }
        alpha[s[i]-'a']=i;
    }
    ll index=0;
    ll ans=0;
    for(int i=0;i<m;i++){
        
        ans+=((maki[index][t[i]-'a']-index+n)%n);
        index=maki[index][t[i]-'a'];
    }
    cout << ans+1<<endl;
    return 0;
}