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Fix bug and edit doctests for infix_to_prefix_conversion #10259

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Merged
merged 6 commits into from
Oct 11, 2023
Merged

Fix bug and edit doctests for infix_to_prefix_conversion #10259

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d503bd8
Fix bug and edit doctests
hollowcrust Oct 11, 2023
da1e869
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Oct 11, 2023
2e8259e
Add type hints, raiseError and other minor adjustments
hollowcrust Oct 11, 2023
ae64862
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Oct 11, 2023
f244936
Cleaning code
hollowcrust Oct 11, 2023
574f83b
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Oct 11, 2023
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52 changes: 43 additions & 9 deletions data_structures/stacks/infix_to_prefix_conversion.py
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Original file line number Diff line number Diff line change
Expand Up @@ -28,14 +28,30 @@ def infix_2_postfix(infix):
| + | abc^
| | abc^+
'abc^+'
>>> infix_2_postfix("1*((-a)*2+b)")
Traceback (most recent call last):
...
KeyError: '('

>>> infix_2_postfix("1*((-a)*2+b)") # doctest: +NORMALIZE_WHITESPACE
Symbol | Stack | Postfix
-------------------------------------------
1 | | 1
* | * | 1
( | *( | 1
( | *(( | 1
- | *((- | 1
a | *((- | 1a
) | *( | 1a-
* | *(* | 1a-
2 | *(* | 1a-2
+ | *(+ | 1a-2*
b | *(+ | 1a-2*b
) | * | 1a-2*b+
| | 1a-2*b+*
'1a-2*b+*'

>>> infix_2_postfix("")
Symbol | Stack | Postfix
----------------------------
''

>>> infix_2_postfix("(()") # doctest: +NORMALIZE_WHITESPACE
Symbol | Stack | Postfix
----------------------------
Expand All @@ -44,6 +60,7 @@ def infix_2_postfix(infix):
) | ( |
| | (
'('

>>> infix_2_postfix("())")
Traceback (most recent call last):
...
Expand Down Expand Up @@ -83,7 +100,11 @@ def infix_2_postfix(infix):
if len(stack) == 0:
stack.append(x) # If stack is empty, push x to stack
else: # while priority of x is not > priority of element in the stack
while len(stack) > 0 and priority[x] <= priority[stack[-1]]:
while (
len(stack) > 0
and stack[-1] != "("
and priority[x] <= priority[stack[-1]]
):
post_fix.append(stack.pop()) # pop stack & add to Postfix
stack.append(x) # push x to stack

Expand Down Expand Up @@ -119,10 +140,23 @@ def infix_2_prefix(infix):
| | cb^a+
'+a^bc'

>>> infix_2_prefix("1*((-a)*2+b)")
Traceback (most recent call last):
...
KeyError: '('
>>> infix_2_prefix("1*((-a)*2+b)") # doctest: +NORMALIZE_WHITESPACE
Symbol | Stack | Postfix
-------------------------------------------
( | ( |
b | ( | b
+ | (+ | b
2 | (+ | b2
* | (+* | b2
( | (+*( | b2
a | (+*( | b2a
- | (+*(- | b2a
) | (+* | b2a-
) | | b2a-*+
* | * | b2a-*+
1 | * | b2a-*+1
| | b2a-*+1*
'*1+*-a2b'

>>> infix_2_prefix('')
Symbol | Stack | Postfix
Expand Down