8000 Removing "a" label from binarySearch method in playground so it match… · codee/swift-algorithm-club@20236b2 · GitHub
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Chris Pilcher
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Removing "a" label from binarySearch method in playground so it matches BinarySearch.swift. Applying same change to readme.
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‎Binary Search/BinarySearch.playground/Contents.swift

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -7,13 +7,13 @@ let numbers = [11, 59, 3, 2, 53, 17, 31, 7, 19, 67, 47, 13, 37, 61, 29, 43, 5, 4
77
let sorted = numbers.sorted()
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// Using recursive solution
10-
binarySearch(a: sorted, key: 2, range: 0 ..< sorted.count) // gives 0
11-
binarySearch(a: sorted, key: 67, range: 0 ..< sorted.count) // gives 18
12-
binarySearch(a: sorted, key: 43, range: 0 ..< sorted.count) // gives 13
13-
binarySearch(a: sorted, key: 42, range: 0 ..< sorted.count) // nil
10+
binarySearch(sorted, key: 2, range: 0 ..< sorted.count) // gives 0
11+
binarySearch(sorted, key: 67, range: 0 ..< sorted.count) // gives 18
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binarySearch(sorted, key: 43, range: 0 ..< sorted.count) // gives 13
13+
binarySearch(sorted, key: 42, range: 0 ..< sorted.count) // nil
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// Using iterative solution
16-
binarySearch(a: sorted, key: 2) // gives 0
17-
binarySearch(a: sorted, key: 67) // gives 18
18-
binarySearch(a: sorted, key: 43) // gives 13
19-
binarySearch(a: sorted, key: 42) // nil
16+
binarySearch(sorted, key: 2) // gives 0
17+
binarySearch(sorted, key: 67) // gives 18
18+
binarySearch(sorted, key: 43) // gives 13
19+
binarySearch(sorted, key: 42) // nil

‎Binary Search/BinarySearch.playground/Sources/BinarySearch.swift

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -13,15 +13,15 @@ import Foundation
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// The recursive version of binary search.
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16-
public func binarySearch<T: Comparable>(a: [T], key: T, range: Range<Int>) -> Int? {
16+
public func binarySearch<T: Comparable>(_ a: [T], key: T, range: Range<Int>) -> Int? {
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if range.lowerBound >= range.upperBound {
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return nil
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} else {
2020
let midIndex = range.lowerBound + (range.upperBound - range.lowerBound) / 2
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if a[midIndex] > key {
22-
return binarySearch(a: a, key: key, range: range.lowerBound ..< midIndex)
22+
return binarySearch(a, key: key, range: range.lowerBound ..< midIndex)
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} else if a[midIndex] < key {
24-
return binarySearch(a: a, key: key, range: midIndex + 1 ..< range.upperBound)
24+
return binarySearch(a, key: key, range: midIndex + 1 ..< range.upperBound)
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} else {
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return midIndex
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}
@@ -35,7 +35,7 @@ public func binarySearch<T: Comparable>(a: [T], key: T, range: Range<Int>) -> In
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uses a while loop, while the other calls itself recursively.
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**/
3737

38-
public func binarySearch<T: Comparable>(a: [T], key: T) -> Int? {
38+
public func binarySearch<T: Comparable>(_ a: [T], key: T) -> Int? {
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var lowerBound = 0
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var upperBound = a.count
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while lowerBound < upperBound {

‎Binary Search/README.markdown

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@ numbers.indexOf(43) // returns 15
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The built-in `indexOf()` function performs a [linear search](../Linear Search/). In code that looks something like this:
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```swift
18-
func linearSearch<T: Equatable>(a: [T], _ key: T) -> Int? {
18+
func linearSearch<T: Equatable>(_ a: [T], _ key: T) -> Int? {
1919
for i in 0 ..< a.count {
2020
if a[i] == key {
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return i
@@ -45,7 +45,7 @@ Sounds great, but there is a downside to using binary search: the array must be
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Here's how binary search works:
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48-
- Split the array in half and determine whether the thing you're looking for, known as the *search key*, is in the left half or in the right half.
48+
- Split the array in half and determine whether the thing you're looking for, known as the *search key*, is in the left half or in the right half.
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- How do you determine in which half the search key is? This is why you sorted the array first, so you can do a simple `<` or `>` comparison.
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- If the search key is in the left half, you repeat the process there: split the left half into two even smaller pieces and look in which piece the search key must lie. (Likewise for when it's the right half.)
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- This repeats until the search key is found. If the array cannot be split up any further, you must regrettably conclude that the search key is not present in the array.
@@ -57,7 +57,7 @@ Now you know why it's called a "binary" search: in every step it splits the arra
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Here is a recursive implementation of binary search in Swift:
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```swift
60-
func binarySearch<T: Comparable>(a: [T], key: T, range: Range<Int>) -> Int? {
60+
func binarySearch<T: Comparable>(_ a: [T], key: T, range: Range<Int>) -> Int? {
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if range.lowerBound >= range.upperBound {
6262
// If we get here, then the search key is not present in the array.
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return nil
@@ -180,7 +180,7 @@ Binary search is recursive in nature because you apply the same logic over and o
180180
Here is an iterative implementation of binary search in Swift:
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```swift
183-
func binarySearch<T: Comparable>(a: [T], key: T) -> Int? {
183+
func binarySearch<T: Comparable>(_ a: [T], key: T) -> Int? {
184184
var lowerBound = 0
185185
var upperBound = a.count
186186
while lowerBound < upperBound {

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