Obtain The String

题意翻译

给定两个字符串 $s$ 和 $t$。有一个初始为空的字符串 $z$，每次操作可以往 $z$ 的末尾加上一个 $s$ 的子序列，问至少经过多少次操作才能使 $z$ 变成 $t$，如果不可能输出 $-1$。

题目描述

You are given two strings $ s $ and $ t $ consisting of lowercase Latin letters. Also you have a string $ z $ which is initially empty. You want string $ z $ to be equal to string $ t $ . You can perform the following operation to achieve this: append any subsequence of $ s $ at the end of string $ z $ . A subsequence is a sequence that can be derived from the given sequence by deleting zero or more elements without changing the order of the remaining elements. For example, if $ z = ac $ , $ s = abcde $ , you may turn $ z $ into following strings in one operation: 1. $ z = acace $ (if we choose subsequence $ ace $ ); 2. $ z = acbcd $ (if we choose subsequence $ bcd $ ); 3. $ z = acbce $ (if we choose subsequence $ bce $ ). Note that after this operation string $ s $ doesn't change. Calculate the minimum number of such operations to turn string $ z $ into string $ t $ .

输入输出格式

输入格式

The first line contains the integer $ T $ ( $ 1 \le T \le 100 $ ) — the number of test cases. The first line of each testcase contains one string $ s $ ( $ 1 \le |s| \le 10^5 $ ) consisting of lowercase Latin letters. The second line of each testcase contains one string $ t $ ( $ 1 \le |t| \le 10^5 $ ) consisting of lowercase Latin letters. It is guaranteed that the total length of all strings $ s $ and $ t $ in the input does not exceed $ 2 \cdot 10^5 $ .

输出格式

For each testcase, print one integer — the minimum number of operations to turn string $ z $ into string $ t $ . If it's impossible print $ -1 $ .

输入输出样例

输入样例 #1

3
aabce
ace
abacaba
aax
ty
yyt

输出样例 #1

1
-1
3