Color with Occurrences
Contest: Codeforces Round 811 (Div. 3)
Difficulty rating: 1600
Tags: brute force, data structures, dp, greedy, strings

You are given some text $$$t$$$ and a set of $$$n$$$ strings $$$s_1, s_2, \dots, s_n$$$.

In one step, you can choose any occurrence of any string $$$s_i$$$ in the text $$$t$$$ and color the corresponding characters of the text in red. For example, if $$$t=\texttt{bababa}$$$ and $$$s_1=\texttt{ba}$$$, $$$s_2=\texttt{aba}$$$, you can get $$$t=\color{red}{\texttt{ba}}\texttt{baba}$$$, $$$t=\texttt{b}\color{red}{\texttt{aba}}\texttt{ba}$$$ or $$$t=\texttt{bab}\color{red}{\texttt{aba}}$$$ in one step.

You want to color all the letters of the text $$$t$$$ in red. When you color a letter in red again, it stays red.

In the example above, three steps are enough:

- Let's color $$$t[2 \dots 4]=s_2=\texttt{aba}$$$ in red, we get $$$t=\texttt{b}\color{red}{\texttt{aba}}\texttt{ba}$$$;
- Let's color $$$t[1 \dots 2]=s_1=\texttt{ba}$$$ in red, we get $$$t=\color{red}{\texttt{baba}}\texttt{ba}$$$;
- Let's color $$$t[4 \dots 6]=s_2=\texttt{aba}$$$ in red, we get $$$t=\color{red}{\texttt{bababa}}$$$.

Each string $$$s_i$$$ can be applied any number of times (or not at all). Occurrences for coloring can intersect arbitrarily.

Determine the minimum number of steps needed to color all letters $$$t$$$ in red and how to do it. If it is impossible to color all letters of the text $$$t$$$ in red, output -1.

Input format:
The first line of the input contains an integer $$$q$$$ ($$$1 \le q \le 100$$$) —the number of test cases in the test.

The descriptions of the test cases follow.

The first line of each test case contains the text $$$t$$$ ($$$1 \le |t| \le 100$$$), consisting only of lowercase Latin letters, where $$$|t|$$$ is the length of the text $$$t$$$.

The second line of each test case contains a single integer $$$n$$$ ($$$1 \le n \le 10$$$) — the number of strings in the set.

This is followed by $$$n$$$ lines, each containing a string $$$s_i$$$ ($$$1 \le |s_i| \le 10$$$) consisting only of lowercase Latin letters, where $$$|s_i|$$$ — the length of string $$$s_i$$$.

Output format:
For each test case, print the answer on a separate line.

If it is impossible to color all the letters of the text in red, print a single line containing the number -1.

Otherwise, on the first line, print the number $$$m$$$ — the minimum number of steps it will take to turn all the letters $$$t$$$ red.

Then in the next $$$m$$$ lines print pairs of indices: $$$w_j$$$ and $$$p_j$$$ ($$$1 \le j \le m$$$), which denote that the string with index $$$w_j$$$ was used as a substring to cover the occurrences starting in the text $$$t$$$ from position $$$p_j$$$. The pairs can be output in any order.

If there are several answers, output any of them.

Constraints:
Time limit: 2.0 s
Memory limit: 256.0 MB

Note:
The first test case is explained in the problem statement.

In the second test case, it is impossible to color all the letters of the text in red.

Example input:
6
bababa
2
ba
aba
caba
2
bac
acab
abacabaca
3
aba
bac
aca
baca
3
a
c
b
codeforces
4
def
code
efo
forces
aaaabbbbcccceeee
4
eeee
cccc
aaaa
bbbb

Example output:
3
2 2
1 1
2 4
-1
4
1 1
2 6
3 3
3 7
4
3 1
1 2
2 3
1 4
2
4 5
2 1
4
3 1
4 5
2 9
1 13

Editorial:
The first step is to find the word that covers the maximum length prefix. If there is no such word, we cannot color the string.
Then go through the positions inside the found prefix and find the next word, which is a tweak of $$$t$$$, has the maximal length, and ends not earlier than the previous found word, and not later than the text $$$t$$$. If there is no such word, it is impossible to color $$$t$$$.
After the second word is found, similarly continue looking for the next ones.