Skip to content

Add practice exercise: poker #203

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
IsaacG merged 1 commit into from
Sep 7, 2025
Merged

Add practice exercise: poker #203

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 8 additions & 0 deletions config.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -450,6 +450,14 @@
"prerequisites": [],
"difficulty": 8
},
{
"slug": "poker",
"name": "Poker",
"uuid": "b9ec94e1-8c20-4095-b627-889b614e2a99",
"practices": [],
"prerequisites": [],
"difficulty": 8
},
{
"slug": "protein-translation",
"name": "Protein Translation",
Expand Down
7 changes: 7 additions & 0 deletions exercises/practice/poker/.docs/instructions.append.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
# SQLite-specific instructions

## JSON documentation

See [JSON Functions And Operators][json-docs] for SQLite JSON functions.

[json-docs]: https://www.sqlite.org/json1.html
7 changes: 7 additions & 0 deletions exercises/practice/poker/.docs/instructions.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
# Instructions

Pick the best hand(s) from a list of poker hands.

See [Wikipedia][poker-hands] for an overview of poker hands.

[poker-hands]: https://en.wikipedia.org/wiki/List_of_poker_hands
19 changes: 19 additions & 0 deletions exercises/practice/poker/.meta/config.json
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
{
"authors": [
"jimmytty"
],
"files": {
"solution": [
"poker.sql"
],
"test": [
"poker_test.sql"
],
"example": [
".meta/example.sql"
]
},
"blurb": "Pick the best hand(s) from a list of poker hands.",
"source": "Inspired by the training course from Udacity.",
"source_url": "https://www.udacity.com/course/design-of-computer-programs--cs212"
}
291 changes: 291 additions & 0 deletions exercises/practice/poker/.meta/example.sql
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,291 @@
DROP TABLE IF EXISTS ranking;
CREATE TEMPORARY TABLE ranking (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL
);
INSERT INTO ranking (id, name)
VALUES
(10, 'straight flush' ),
(20, 'four of a kind' ),
(30, 'full house' ),
(40, 'flush' ),
(50, 'straight' ),
(60, 'three of a kind'),
(70, 'two pair' ),
(80, 'one pair' ),
(90, 'high card' )
;

DROP TABLE IF EXISTS tmp;
CREATE TABLE tmp (
hand TEXT PRIMARY KEY,
deck TEXT,
name TEXT
);
INSERT INTO tmp (hand)
SELECT DISTINCT(j.value)
FROM poker, JSON_TREE(hands) j
WHERE j.type = 'text'
;

UPDATE tmp
SET deck = (
WITH to_cards (rank, suite) AS (
WITH RECURSIVE to_cards (hand, card) AS (
VALUES (hand || ' ', NULL)
UNION ALL
SELECT
SUBSTR(hand, INSTR(hand, ' ') + 1),
SUBSTR(hand, 1, INSTR(hand, ' ') - 1)
FROM to_cards
WHERE hand <> ''
LIMIT 10
)
SELECT SUBSTR(card, 1, LENGTH(card) - 1) AS rank,
SUBSTR(card, -1) AS suite
FROM to_cards
WHERE card NOTNULL
)
SELECT JSON_GROUP_ARRAY(JSON(card))
FROM (
SELECT JSON_ARRAY(rank, suite) card
FROM (
SELECT
CASE rank
WHEN 'A' THEN 14
WHEN 'J' THEN 11
WHEN 'Q' THEN 12
WHEN 'K' THEN 13
ELSE rank
END * 1 AS rank,
suite
FROM to_cards
)
ORDER BY rank DESC, suite ASC
)
)
;

ALTER TABLE tmp ADD COLUMN is_sequential BOOLEAN;
UPDATE tmp
SET is_sequential =
(SELECT JSON_ARRAY_LENGTH(ranks) = 5
AND JSON_EXTRACT(ranks, '$[0]') =
JSON_EXTRACT(ranks, '$[4]') + 4
FROM (SELECT
JSON_GROUP_ARRAY(
DISTINCT(JSON_EXTRACT(j.value, '$[0]'))) AS ranks
FROM JSON_EACH(deck) j))
OR
(SELECT JSON_ARRAY_LENGTH(ranks) = 5
AND JSON_EXTRACT(ranks, '$[0]') =
JSON_EXTRACT(ranks, '$[4]') + 4
FROM (
SELECT JSON_GROUP_ARRAY(rank) AS ranks
FROM (
SELECT IIF(rank = 14, 1, rank) rank
FROM (
SELECT DISTINCT(JSON_EXTRACT(j.value, '$[0]')) AS rank
FROM JSON_EACH(deck) j
)
ORDER BY rank DESC
)
)
)
;

ALTER TABLE tmp ADD COLUMN same_suite BOOLEAN;
UPDATE tmp
SET same_suite = (
SELECT JSON_ARRAY_LENGTH(suites) = 1
FROM (
SELECT JSON_GROUP_ARRAY(
DISTINCT(JSON_EXTRACT(j.value, '$[1]'))
) AS suites
FROM JSON_EACH(deck) j
)
)
;

UPDATE tmp
SET name = 'straight flush'
WHERE is_sequential AND same_suite
AND name ISNULL
;

UPDATE tmp
SET name = 'four of a kind'
WHERE (SELECT 1
FROM (
SELECT JSON_EXTRACT(j.value, '$[0]') rank
FROM JSON_EACH(deck) j
)
GROUP BY rank
HAVING COUNT(*) = 4
)
AND name ISNULL
;

UPDATE tmp
SET name = 'full house'
WHERE (SELECT GROUP_CONCAT(dup) = '3,2'
FROM (
SELECT dup
FROM (
SELECT COUNT(*) dup
FROM (
SELECT JSON_EXTRACT(j.value, '$[0]') rank
FROM JSON_EACH(deck) j
)
GROUP BY rank
)
ORDER BY dup DESC
)
)
AND name ISNULL
;

UPDATE tmp
SET name = 'flush'
WHERE same_suite
AND name ISNULL
;

UPDATE tmp
SET name = 'straight'
WHERE is_sequential
AND name ISNULL
;

UPDATE tmp
SET name = 'three of a kind'
WHERE (SELECT 1
FROM (
SELECT JSON_EXTRACT(j.value, '$[0]') rank
FROM JSON_EACH(deck) j
)
GROUP BY rank
HAVING COUNT(*) = 3
)
AND name ISNULL
;

UPDATE tmp
SET name = 'two pair'
WHERE (SELECT GROUP_CONCAT(dup) = '2,2,1'
FROM (
SELECT dup
FROM (
SELECT COUNT(*) dup
FROM (
SELECT JSON_EXTRACT(j.value, '$[0]') rank
FROM JSON_EACH(deck) j
)
GROUP BY rank
)
ORDER BY dup DESC
)
)
AND name ISNULL
;

UPDATE tmp
SET name = 'one pair'
WHERE (SELECT 1
FROM (
SELECT JSON_EXTRACT(j.value, '$[0]') rank
FROM JSON_EACH(deck) j
)
GROUP BY rank
HAVING COUNT(*) = 2
)
AND name ISNULL
;

UPDATE tmp
SET name = 'high card'
WHERE name ISNULL
;

ALTER TABLE tmp ADD COLUMN ranks_id INTEGER;
UPDATE tmp
SET ranks_id =
CASE
WHEN name NOT IN ('four of a kind', 'three of a kind', 'full house')
THEN (
(SELECT GROUP_CONCAT(rank, '')
FROM (
SELECT IIF(rank = '14' AND
LIKE('straight%', name) AND
JSON_EXTRACT(
deck, '$[0][0]', '$[1][0]') = JSON_ARRAY(14,5),
1,
rank
) rank
FROM (
SELECT PRINTF('%02d', JSON_EXTRACT(j.value, '$[0]')) rank
FROM JSON_EACH(deck) j
)
ORDER BY rank DESC
)
)
)
ELSE (
WITH
by_rank AS (
SELECT JSON_EXTRACT(j.value, '$[0]') rank, j.*
FROM JSON_EACH(deck) j
),
dup (rank) AS (
SELECT rank
FROM by_rank
GROUP BY rank
ORDER BY COUNT(*) DESC
LIMIT 1
),
same (rank) AS (
SELECT PRINTF('%02d', by_rank.rank)
FROM by_rank, dup
WHERE by_rank.rank = dup.rank
),
kickers (rank) AS (
SELECT PRINTF('%02d', by_rank.rank)
FROM by_rank, dup
WHERE by_rank.rank != dup.rank
ORDER BY by_rank.rank DESC
)
SELECT GROUP_CONCAT(rank, '')
FROM (
SELECT rank FROM same
UNION ALL
SELECT rank FROM kickers
)
)
END
;



UPDATE poker
SET result = (
WITH
analysis AS (
SELECT j.value hand, tmp.name, tmp.deck, ranking.id, tmp.ranks_id
FROM JSON_TREE(hands) j, tmp, ranking
WHERE j.value = tmp.hand
AND tmp.name = ranking.name
AND j.type = 'text'
),
winners AS (
SELECT hand, ranks_id
FROM analysis WHERE id = (SELECT MIN(id) FROM analysis)
),
tiebreaker AS (
SELECT winners.hand
FROM winners
WHERE ranks_id = (SELECT MAX(ranks_id) FROM winners)
)
SELECT JSON_GROUP_ARRAY(hand)
FROM (SELECT hand FROM tiebreaker ORDER BY hand)
)
;
Loading