51 lines
1.0 KiB
Markdown
51 lines
1.0 KiB
Markdown
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## Machine Fix
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The main idea finding the flag is just understanding the algorithm.
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#### Step-1:
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After I downloaded `code.py`, I tried to understand the workflow here:
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```python
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def convert (n):
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if n == 0:
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return '0'
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nums = []
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while n:
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n, r = divmod(n, 3)
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nums.append(str(r))
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return ''.join(reversed(nums))
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count=0
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n=1
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while(n<=523693181734689806809285195318):
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str1=convert(n)
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str2=convert(n-1)
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str2='0'*(len(str1)-len(str2))+str2
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for i in range(len(str1)):
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if(str1[i]!=str2[i]):
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count+=1
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n+=1
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print(count)
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```
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#### Step-2:
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For every number n, n and n - 1 are converted to base 3 & then, the program compare the digits, the number of differences is added to total.
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So I wrote a simple `flag.py` script to get flag:
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```python
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def flag(n):
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sum = 0
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while (n > 0):
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sum += n
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n //= 3
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return sum
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print(flag(523693181734689806809285195318))
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```
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On running it by `python3 flag.py`
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#### Step-3:
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Finally the flag becomes:
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`csictf{785539772602034710213927792950}`
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