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<vector>
#include<utility>
#include<algorithm>
#include<string>
#include<cstdio>
#include<queue>
using namespace std;
int main() {
	string t,s; cin >> t;
	vector<vector<int>>data(26);
	int tl = t.length();
	for (int i = 0; i < tl; ++i) 
		data[t[i] - 'a'].push_back(i+1);
	long long last = 0;
	int n = 0;
	cin >> t;
	for (int i = 0; i < tl; ++i) {
		int x = t[i] - 'a';
		if (data[x].empty()) {
			cout << "-1" << endl; return 0;
		}
		if (data[x][data[x].size() - 1] + tl * n <= last) {
			++n;
			last -= tl;
		}
		for (int j = 0; j < data[x].size(); ++j) {
			if ((data[x][j]) > last) {
				last = data[x][j];
				break;
			}
		}
	}
	cout << last << endl;
	return 0;
}