Contest Duration: - (local time) (100 minutes) Back to Home
E - Strings of Impurity /

Time Limit: 2 sec / Memory Limit: 1024 MB

### 問題文

• s10^{100} 個連結して得られる文字列を s' とする。t は、文字列 {s'}_1{s'}_2\ldots{s'}_i (s' の先頭 i 文字) の部分列である。

### 注記

• 文字列 a の部分列とは、a から 0 文字以上を削除して残った文字を相対的な順序を保ったまま連結して得られる文字列です。例えば、contest の部分列には net, c, contest などがあります。

### 制約

• 1 \leq |s| \leq 10^5
• 1 \leq |t| \leq 10^5
• s, t は英小文字からなる。

s
t

contest
son

### 出力例 1

10

t = son は文字列 contestcon (s' = contestcontestcontest... の先頭 10 文字) の部分列であるため、i = 10 は条件を満たします。

contest
programming

### 出力例 2

-1

t = programmings' = contestcontestcontest... の部分列ではありません。よって、条件を満たす整数 i は存在しません。

contest
sentence

### 出力例 3

33

ここにそのようなケースを置くことはできませんが、答えは 32 bit 整数に収まらない可能性があるのでご注意ください。

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.

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.

contest
programming

### Sample Output 2

-1

t = programming is not a substring of s' = contestcontestcontest.... Thus, there is no integer i satisfying the condition.

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.