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>
using namespace std;

string s, t;
int a[27][100010];
int slen, tlen;
long long ans = 0;

void solve(){
    int temp;
    for (int i = 0; i < tlen; ++i) {
        long long min_ = 1000000000000000000;
        for (int j = 0; j < slen; ++j) {
            temp = a[t[i] - 97][j];
            if (temp == 0) {
                ans = -1;
                return;
            }
            long long n = temp - (ans % (slen/2)) - 1;
            if (temp - 1 > ans % (slen/2) && min_ > n) {
                min_ = n;
                break;
            }
        }
        ans += min_;
    }
}

int main() {
    cin >> s >> t;
    string s_ = s + s;
    slen = s_.length();
    tlen = t.length();

    for (int i = 0; i < slen; ++i) {
        for (int j = 0; j < slen - i; ++j) {
            if (a[s_[i] - 97][j] == 0) {
                a[s_[i] - 97][j] = i + 1;
                break;
            }
        }
    }

    solve();
    cout << ans + 1 << endl;

    return 0;
}