apps_527
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----- contest son
-----Sample Output----- 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.
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