58 lines
1.9 KiB
Markdown
58 lines
1.9 KiB
Markdown
# Practice things
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_just going through the practice midterm problems_
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1. Identifying sorting algorithms based on progression(_conceptual_)
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_bubble sort_: the bigger the value = the bigger the bubble
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* compare two values from the start always, bubble up the bigger value
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keep compmaring two adjacent values till you get to the end of the list
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* kinda like gladiator m&m's
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_insertion sort_: we have the left sublist which maintains a ordered state always
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* we walk along the unsorted list and try to drop our current value into the currently sorted left-hand sublist.
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* Key points:
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left hand ordered sublist
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_quick sort_: here we push things up to the top immediately where they are then sorted against the left hand sub-list
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_heap sort_: make a giant heap(list) and just take the largest/smallest value and prepend/append to the """heap"""
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__reponse__: insertion sort
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Left side of progression is always sorted while the right isn't
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Left side also get progressively larger
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2. How you know if a graph is undirected given a matrix(_code_)
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_empirically_: check the upper right half of the matrix and check if each coord pair is reflected across the main axis
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1. Take a coords pair value(_say True_)
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2. Flip the (x,y) so we have /x,y/
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3. If the /x,y/ value is the same as (x,y) then those two nodes are bidrectional(i.e. undirected)
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The _trick_ here is making sure we don't bother check the divisor axis or below by accident.
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3. Binary tree lookup(_code_)
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Recursion is the smollest way of doing this so just go with that.
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4. Quick sort partition(_code_)
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* Just splitting lists again
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* Checking for partition results as well
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5. Graph traversal(_code_)
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DFS/BFS is fair game
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List/matrix meme allowed so don't even bother with other trash
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6. Emperical Graph Traversal(_conceptual_)
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Time complexity of either dfs/bfs will be /v\*e/ or something like that
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7. Topological sort(_code_)
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big meme matrix/list allowed
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