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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		char[] s = in.next().toCharArray(), q = in.next().toCharArray();
		long i = 0;

		Map<Character, list> alf = new HashMap<>();

		for(int j = 0; j < s.length; j++) {
			if(alf.containsKey(s[j])) {
				alf.get(s[j]).add(j);
			}else {
				alf.put(s[j], new list(j));
			}
		}
		for(int j = 0; j < q.length; j++) {
			if(!alf.containsKey(q[j])) {
				System.out.println(-1);
				return;
			}
		}

		int lim = 0;
		int qInd = 0;
		int back = 0;
		while(lim < 100 && qInd < q.length) {
			int sInd = alf.get(q[qInd]).getNow();
			i += sInd - back;
			if(sInd < back) {
				i += s.length;
				lim++;
			}
			back = sInd;
			qInd++;
		}

		if(lim == 100) {
			System.out.println(-1);
		}else {
			System.out.println(i);
		}
		return;
	}
}

class list{
	ArrayList<Integer> ind = new ArrayList<Integer>();
	int now;
	public list(int n) {
		ind.add(n);
		now = 0;
	}

	public void add(int n) {
		ind.add(n);
	}

	public int getNow() {
		if(now >= ind.size())
			now = 0;
		int re = ind.get(now)+1;
		now++;
		return re;

	}

}