9623: ABC257 —— G - Prefix Concatenation
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Description
You are given two strings $S$ and $T$ consisting of lowercase English letters.
Find the minimum positive integer $k$ such that you can choose (not necessarily distinct) $k$ prefixes of $S$ so that their concatenation coincides with $T$.
In other words, find the minimum positive integer $k$ such that there exists a $k$-tuple $(a_1,a_2,\ldots, a_k)$ of integers between $1$ and $|S|$ such that
$T=S_{a_1}+S_{a_2}+\cdots +S_{a_k}$, where $S_i$ denotes the substring of $S$ from the $1$-st through the $i$-th characters and $+$ denotes the concatenation of strings.
If it is impossible to make it coincide with $T$, print $-1$ instead.
Find the minimum positive integer $k$ such that you can choose (not necessarily distinct) $k$ prefixes of $S$ so that their concatenation coincides with $T$.
In other words, find the minimum positive integer $k$ such that there exists a $k$-tuple $(a_1,a_2,\ldots, a_k)$ of integers between $1$ and $|S|$ such that
$T=S_{a_1}+S_{a_2}+\cdots +S_{a_k}$, where $S_i$ denotes the substring of $S$ from the $1$-st through the $i$-th characters and $+$ denotes the concatenation of strings.
If it is impossible to make it coincide with $T$, print $-1$ instead.
Input
Input is given from Standard Input in the following format:
```
$S$
$T$
```
```
$S$
$T$
```
Output
Print the minimum positive integer $k$ such that you can choose $k$ prefixes of $S$ so that their concatenation coincides with $T$. It is impossible to make it coincide with $T$, print $-1$ instead.
Constraints
- $1 \leq |S| \leq 5\times 10^5$
- $1 \leq |T| \leq 5\times 10^5$
- $S$ and $T$ are strings consisting of lowercase English letters.
- $1 \leq |T| \leq 5\times 10^5$
- $S$ and $T$ are strings consisting of lowercase English letters.
Sample 1 Input
aba
ababaab
Sample 1 Output
3
T= ababaab can be written as ab + aba + ab, of which ab and aba are prefixes of S= aba.
Since it is unable to express ababaab with two or less prefixes of aba, print 3.
Since it is unable to express ababaab with two or less prefixes of aba, print 3.
Sample 2 Input
atcoder
ac
Sample 2 Output
-1
Since it is impossible to express T as a concatenation of prefixes of S, print −1−1.