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alias_pairs

Your mission

Implement alias_pairs, which returns every pair of positions of rows that hold one and the same list object.

See it in action

alias_pairs([(a := [1, 2]), [1, 2], a]): [(0, 2)]
alias_pairs([[5], (b := [6]), b, [5]]): [(1, 2)]
alias_pairs([[], []]): []

Your checklist

rows is a list of 0 or more lists of int. The same list object may appear at several positions of rows.
A pair is two positions i < j where rows[i] and rows[j] are one and the same object. Two separate lists with equal contents are not a pair.
Return every pair as a tuple (i, j), sorted by i, then by j. Return [] when there is none.
Do not modify rows or the lists it contains.

Constraints

Expected file: alias_pairs.py
Allowed functions: None. Write every helper yourself.

Run the tests to grade your code

15 tests

No rows gives no pair
A single row is never paired with itself
Equal but separate lists are not pairs
One list at two positions
Aliases side by side
Aliases at the first and last positions
Empty lists: only the shared one forms a pair
One list at three positions gives three pairs
One list at four positions gives six pairs
Aliases mixed with equal copies
Pairs sorted by first position, not by second
Three lists with equal contents, each repeated
All rows distinct
Two lists repeated in turn
rows and its lists are left unchanged

Python

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Learn
Exercises
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alias_pairs

Your mission

Implement alias_pairs, which returns every pair of positions of rows that hold one and the same list object.

See it in action

alias_pairs([(a := [1, 2]), [1, 2], a]): [(0, 2)]
alias_pairs([[5], (b := [6]), b, [5]]): [(1, 2)]
alias_pairs([[], []]): []

Your checklist

rows is a list of 0 or more lists of int. The same list object may appear at several positions of rows.
A pair is two positions i < j where rows[i] and rows[j] are one and the same object. Two separate lists with equal contents are not a pair.
Return every pair as a tuple (i, j), sorted by i, then by j. Return [] when there is none.
Do not modify rows or the lists it contains.

Constraints

Expected file: alias_pairs.py
Allowed functions: None. Write every helper yourself.

Run the tests to grade your code

15 tests

No rows gives no pair
A single row is never paired with itself
Equal but separate lists are not pairs
One list at two positions
Aliases side by side
Aliases at the first and last positions
Empty lists: only the shared one forms a pair
One list at three positions gives three pairs
One list at four positions gives six pairs
Aliases mixed with equal copies
Pairs sorted by first position, not by second
Three lists with equal contents, each repeated
All rows distinct
Two lists repeated in turn
rows and its lists are left unchanged

Variables will appear here

Python