You are required to read and try to understand a competitive programming problem statement and interpret its correct solution. Think carefully about why doing this can correctly solve the problem.
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Here's an accepted solution from an expert programmer. Can you analyze the code and identify the algorithmic approach used? Please also describe the steps of the algorithm in natural language, explaining what every named variable means, what each step does and how it works. If there is anything non-obvious in the step, explain why it is done. Please notice that in the algorithm, some conclusions might be first deduced from conditions and directly used.
```
for _ in range(int(input())):
    n,q=map(int,input().split())
    ls=list(map(int,input().split()))
    ans=['0']*n
    iq=0
    for i in range(n-1,-1,-1):
        if ls[i]<=iq:
            ans[i]='1'
        elif iq<q:
            iq+=1
            ans[i]='1'
 
    print(''.join(ans))
```
Analyze the problem and the accepted code of the correct solution. 
Avoid ambiguity in your description as possible. 
Each part should be independently interpretable, i.e., each point should be clear to readers who have no access to other points.  
Answer in the following Format: 
1). Brief Problem Summary: 
2). Used Algorithm: 
3). Step-to-step Solution Description: 
4). Explanation of the Solution: 
5). Solution in one sentence: 
6). Time Complexity: 
7). Proof of correctness: 
8). Conclusions deduced from given conditions that make Solution correct: 
9 Do not say the word "format" in the response
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