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new exercise: saddle-points
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‎config.json

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"uuid": "9edd0fda-cc73-40a2-a32c-b16918c65167",
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"practices": [],
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"prerequisites": [],
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"difficulty": 2
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},
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{
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"slug": "saddle-points",
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"name": "Saddle Points",
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"uuid": "5efb23b7-fa38-4667-a344-4455877beb03",
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"practices": [],
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"prerequisites": [],
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"difficulty": 4
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}
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]

‎exercises/practice/saddle-points/.docs/instructions.append.md

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## Input format
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The input will be in the format of a string. To keep this exercise beginner-friendly, you need not expect numbers with multiple digits.
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Bytes 64-191 of the linear memory are reserved for the input string.
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## Output format
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The output is expected in pairs of row and column as u8 directly concatenated.

‎exercises/practice/saddle-points/.docs/instructions.md

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# Instructions
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Your task is to find the potential trees where you could build your tree house.
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The data company provides the data as grids that show the heights of the trees.
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The rows of the grid represent the east-west direction, and the columns represent the north-south direction.
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An acceptable tree will be the largest in its row, while being the smallest in its column.
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A grid might not have any good trees at all.
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Or it might have one, or even several.
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Here is a grid that has exactly one candidate tree.
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```text
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↓
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1 2 3 4
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|-----------
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1 | 9 8 7 8
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→ 2 |[5] 3 2 4
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3 | 6 6 7 1
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```
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- Row 2 has values 5, 3, 2, and 4. The largest value is 5.
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- Column 1 has values 9, 5, and 6. The smallest value is 5.
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So the point at `[2, 1]` (row: 2, column: 1) is a great spot for a tree house.

‎exercises/practice/saddle-points/.docs/introduction.md

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# Introduction
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You plan to build a tree house in the woods near your house so that you can watch the sun rise and set.
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You've obtained data from a local survey company that show the height of every tree in each rectangular section of the map.
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You need to analyze each grid on the map to find good trees for your tree house.
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A good tree is both:
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- taller than every tree to the east and west, so that you have the best possible view of the sunrises and sunsets.
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- shorter than every tree to the north and south, to minimize the amount of tree climbing.

‎exercises/practice/saddle-points/.eslintrc

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{
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"root": true,
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"extends": "@exercism/eslint-config-javascript",
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"env": {
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"jest": true
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},
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"overrides": [
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{
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"files": [
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"*.spec.js"
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],
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"excludedFiles": [
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"custom.spec.js"
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],
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"extends": "@exercism/eslint-config-javascript/maintainers"
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}
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]
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}

‎exercises/practice/saddle-points/.meta/config.json

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{
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"authors": [
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"atk"
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],
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"files": {
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"solution": [
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"saddle-points.wat"
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],
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"test": [
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"saddle-points.spec.js"
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],
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"example": [
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".meta/proof.ci.wat"
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],
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"invalidator": [
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"package.json"
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]
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},
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"blurb": "Detect saddle points in a matrix.",
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"source": "J Dalbey's Programming Practice problems",
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"source_url": "https://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html",
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"custom": {
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"version.tests.compatibility": "jest-27",
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"flag.tests.task-per-describe": false,
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"flag.tests.may-run-long": false,
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"flag.tests.includes-optional": false
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}
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}

‎exercises/practice/saddle-points/.meta/proof.ci.wat

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(module
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(memory (export "mem") 1)
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(global $outputOffset i32 (i32.const 1280))
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(global $parsedOffset i32 (i32.const 512))
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(global $rowMaxOffset i32 (i32.const 768))
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(global $colMinOffset i32 (i32.const 1024))
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(global $zero i32 (i32.const 48))
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(global $br i32 (i32.const 10))
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;;
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;; Find the points in the matrix that are the largest in row and smallest in column
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;;
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;; @param {i32} $inputOffset - offset of the matrix in linear memory
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;; @param {i32} $inputLength - length of the matrix in linear memory
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;;
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;; @result {(i32,i32)} - offset and length of row-column-pairs in linear memory
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;;
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(func (export "saddlePoints") (param $inputOffset i32) (param $inputLength i32) (result i32 i32)
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(local $row i32)
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(local $column i32)
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(local $lineLength i32)
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(local $rowsLength i32)
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(local $char i32)
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(local $pos i32)
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(local $height i32)
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(local $outputLength i32)
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(if (i32.eqz (local.get $inputLength)) (then (return (global.get $outputOffset) (i32.const 0))))
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(loop $scanInput
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(local.set $char (i32.load8_u (i32.add (local.get $inputOffset) (local.get $pos))))
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(if (i32.ge_u (local.get $char) (global.get $zero))
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(then (local.set $height (i32.add (i32.mul (local.get $height) (i32.const 10))
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(i32.sub (local.get $char) (global.get $zero)))))
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(else (i32.store8 (i32.add (global.get $parsedOffset) (local.get $outputLength)) (local.get $height))
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(local.set $outputLength (i32.add (local.get $outputLength) (i32.const 1))
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(if (i32.gt_u (local.get $height) (i32.load8_u (i32.add (global.get $rowMaxOffset) (local.get $row))))
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(then (i32.store8 (i32.add (global.get $rowMaxOffset) (local.get $row)) (local.get $height))))
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(if (i32.le_u (local.get $height) (i32.sub (i32.load8_u (i32.add (global.get $colMinOffset)
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(local.get $column))) (i32.const 1)))
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(then (i32.store8 (i32.add (global.get $colMinOffset) (local.get $column)) (local.get $height))))
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(local.set $column (i32.add (local.get $column) (i32.const 1)))
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(local.set $height (i32.const 0)))))
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(if (i32.eq (local.get $char) (global.get $br)) (then
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(if (i32.eqz (local.get $lineLength)) (then (local.set $lineLength (local.get $pos))))
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(local.set $row (i32.add (local.get $row) (i32.const 1))
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(local.set $column (i32.const 0)))))
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(local.set $pos (i32.add (local.get $pos) (i32.const 1)))
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(br_if $scanInput (i32.le_u (local.get $pos) (local.get $inputLength))))
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(local.set $rowsLength (i32.add (local.get $row) (i32.const 1)))
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(local.set $lineLength (i32.div_u (local.get $outputLength) (local.get $rowsLength)))
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(local.set $outputLength (i32.const 0))
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(local.set $row (i32.const 0))
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(loop $rows
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(local.set $column (i32.const 0))
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(loop $columns
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(local.set $height (i32.load8_u (i32.add (global.get $parsedOffset)
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(i32.add (i32.mul (local.get $row) (local.get $lineLength)) (local.get $column)))))
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(if (i32.and (i32.eq (local.get $height)
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(i32.load8_u (i32.add (global.get $rowMaxOffset) (local.get $row))))
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(i32.eq (local.get $height) (i32.load8_u (i32.add (global.get $colMinOffset) (local.get $column)))))
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(then (i32.store16 (i32.add (global.get $outputOffset) (local.get $outputLength))
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(i32.or (i32.shl (i32.add (local.get $column) (i32.const 1)) (i32.const 8))
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(i32.add (local.get $row) (i32.const 1))))
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(local.set $outputLength (i32.add (local.get $outputLength) (i32.const 2)))))
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(local.set $column (i32.add (local.get $column) (i32.const 1)))
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(br_if $columns (i32.lt_u (local.get $column) (local.get $lineLength))))
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(local.set $row (i32.add (local.get $row) (i32.const 1)))
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(br_if $rows (i32.lt_u (local.get $row) (local.get $rowsLength))))
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(global.get $outputOffset) (local.get $outputLength)
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)
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)

‎exercises/practice/saddle-points/.meta/tests.toml

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# This is an auto-generated file.
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#
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# Regenerating this file via `configlet sync` will:
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# - Recreate every `description` key/value pair
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# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
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# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
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# - Preserve any other key/value pair
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#
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# As user-added comments (using the # character) will be removed when this file
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# is regenerated, comments can be added via a `comment` key.
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[3e374e63-a2e0-4530-a39a-d53c560382bd]
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description = "Can identify single saddle point"
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[6b501e2b-6c1f-491f-b1bb-7f278f760534]
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description = "Can identify that empty matrix has no saddle points"
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[8c27cc64-e573-4fcb-a099-f0ae863fb02f]
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description = "Can identify lack of saddle points when there are none"
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[6d1399bd-e105-40fd-a2c9-c6609507d7a3]
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description = "Can identify multiple saddle points in a column"
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[3e81dce9-53b3-44e6-bf26-e328885fd5d1]
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description = "Can identify multiple saddle points in a row"
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[88868621-b6f4-4837-bb8b-3fad8b25d46b]
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description = "Can identify saddle point in bottom right corner"
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[5b9499ca-fcea-4195-830a-9c4584a0ee79]
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description = "Can identify saddle points in a non square matrix"
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[ee99ccd2-a1f1-4283-ad39-f8c70f0cf594]
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description = "Can identify that saddle points in a single column matrix are those with the minimum value"
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[63abf709-a84b-407f-a1b3-456638689713]
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description = "Can identify that saddle points in a single row matrix are those with the maximum value"

‎exercises/practice/saddle-points/.npmrc

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audit=false

‎exercises/practice/saddle-points/LICENSE

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MIT License
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Copyright (c) 2021 Exercism
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.

‎exercises/practice/saddle-points/babel.config.js

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export default {
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presets: ["@exercism/babel-preset-javascript"],
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plugins: [],
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};

‎exercises/practice/saddle-points/package.json

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{
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"name": "@exercism/wasm-saddle-points",
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"description": "Exercism exercises in WebAssembly.",
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"author": "Alex Lohr",
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"type": "module",
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"private": true,
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"license": "MIT",
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"repository": {
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"type": "git",
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"url": "https://github.com/exercism/wasm",
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"directory": "exercises/practice/saddle-points"
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},
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"jest": {
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"maxWorkers": 1
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},
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"devDependencies": {
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"@babel/core": "^7.23.3",
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"@exercism/babel-preset-javascript": "^0.4.0",
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"@exercism/eslint-config-javascript": "^0.6.0",
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"@types/jest": "^29.5.8",
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"@types/node": "^20.9.1",
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"babel-jest": "^29.7.0",
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"core-js": "^3.33.2",
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"eslint": "^8.54.0",
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"jest": "^29.7.0"
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},
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"dependencies": {
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"@exercism/wasm-lib": "^0.2.0"
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},
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"scripts": {
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"test": "node --experimental-vm-modules node_modules/jest/bin/jest.js ./*",
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"watch": "node --experimental-vm-modules node_modules/jest/bin/jest.js --watch ./*",
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"lint": "eslint ."
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}
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}

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