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Commit 843eaa6

Browse files
author
Michael Ho
committed
New updates are coming in
1 parent b4d6cc3 commit 843eaa6

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28 files changed

+966
-73
lines changed

28 files changed

+966
-73
lines changed
Lines changed: 70 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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1+
// Leetcode: https://leetcode.com/problems/balanced-binary-tree/
2+
3+
import XCTest
4+
5+
public class TreeNode {
6+
public var val: Int
7+
public var left: TreeNode?
8+
public var right: TreeNode?
9+
public init(_ val: Int) {
10+
self.val = val
11+
self.left = nil
12+
self.right = nil
13+
}
14+
}
15+
16+
class Solution {
17+
func isBalanced(_ root: TreeNode?) -> Bool {
18+
return false
19+
}
20+
21+
private func getTreeHeight(_ node: TreeNode?) {
22+
23+
}
24+
}
25+
26+
class Tests: XCTestCase {
27+
func testSample1() {
28+
let arr = [3, 9, 20, nil, nil, 15, 7]
29+
let root = convertArrToTree(arr)
30+
inOrderPrint(root)
31+
}
32+
33+
private func convertArrToTree(_ arr: [Int?]) -> TreeNode? {
34+
guard arr.count > 0 else {
35+
return nil
36+
}
37+
let root = TreeNode(arr[0]!)
38+
convert(0, root, arr)
39+
return root
40+
}
41+
42+
private func convert(_ index: Int, _ root: TreeNode?, _ arr: [Int?]) {
43+
guard let root = root, index*2 + 2 < arr.count else { return }
44+
45+
if let leftVal = arr[index*2+1] {
46+
root.left = TreeNode(leftVal)
47+
convert(index*2+1, root.left, arr)
48+
}
49+
50+
if let rightVal = arr[index*2+2] {
51+
root.right = TreeNode(rightVal)
52+
convert(index*2+2, root.right, arr)
53+
}
54+
}
55+
56+
func inOrderPrint(_ root: TreeNode?) {
57+
guard let root = root else {
58+
return
59+
}
60+
if let left = root.left {
61+
inOrderPrint(left)
62+
}
63+
print(root.val)
64+
if let right = root.right {
65+
inOrderPrint(right)
66+
}
67+
}
68+
}
69+
70+
Tests.defaultTestSuite.run()
Lines changed: 4 additions & 0 deletions
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<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
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<playground version='5.0' target-platform='ios' executeOnSourceChanges='false'>
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<timeline fileName='timeline.xctimeline'/>
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</playground>
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1+
// LeetCode: https://leetcode.com/problems/find-mode-in-binary-search-tree/
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3+
public class TreeNode {
4+
public var val: Int
5+
public var left: TreeNode?
6+
public var right: TreeNode?
7+
public init(_ val: Int) {
8+
self.val = val
9+
self.left = nil
10+
self.right = nil
11+
}
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}
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14+
class Solution {
15+
func findMode(_ root: TreeNode?) -> [Int] {
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guard let root = root else { return [] }
17+
var dict: [Int:Int] = [:]
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var max = 0
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findMode(root, &dict, &max)
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var output = [Int]()
22+
for i in dict.keys {
23+
if let val = dict[i], val == max {
24+
output.append(i)
25+
}
26+
}
27+
return output
28+
}
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30+
private func findMode(_ root: TreeNode, _ dict: inout [Int:Int], _ max: inout Int) {
31+
if let val = dict[root.val] {
32+
dict[root.val] = val + 1
33+
max = val + 1 > max ? val + 1 : max
34+
} else {
35+
dict[root.val] = 1
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max = 1 > max ? 1 : max
37+
}
38+
39+
if let left = root.left {
40+
findMode(left, &dict, &max)
41+
}
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if let right = root.right {
44+
findMode(right, &dict, &max)
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}
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}
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}
Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
11
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
2-
<playground version='5.0' target-platform='ios'>
2+
<playground version='5.0' target-platform='macos'>
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<timeline fileName='timeline.xctimeline'/>
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</playground>

Easy/0001-TwoSum.playground/Contents.swift renamed to Easy/EasyProblems.playground/Contents.swift

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
// LeetCode: https://leetcode.com/problems/two-sum/description/
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// Solution: https://github.com/zhubofei/LeetCode-Swift/blob/master/0001-two-sum.playground/Contents.swift
33

4-
func twoSum(_ nums: [Int], _ target: Int) -> [Int] {
4+
publicfunc twoSum(_ nums: [Int], _ target: Int) -> [Int] {
55
var dict: [Int: Int] = [:] // [number : indexPosition]
66
for (index, num) in nums.enumerated() {
77
let complement = target - num
Lines changed: 4 additions & 0 deletions
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<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
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<playground version='5.0' target-platform='macos'>
3+
<timeline fileName='timeline.xctimeline'/>
4+
</playground>

‎Medium/0003-LongestSubstringWithoutRepeatingCharacters.playground/Contents.swift‎

Lines changed: 49 additions & 19 deletions
Original file line numberDiff line numberDiff line change
@@ -4,27 +4,51 @@
44
import XCTest
55

66
class Solution {
7+
// func lengthOfLongestSubstring(_ s: String) -> Int {
8+
// guard s.count > 0 else {
9+
// return 0
10+
// }
11+
//
12+
// var maxCount = 1
13+
// if s.count == 1 {
14+
// return maxCount
15+
// }
16+
// let strArr = Array(s) // Key: convert string to array
17+
// for (index, char) in strArr.enumerated() {
18+
// var dict: [Character : Int] = [:]
19+
// var count = 1
20+
// dict[char] = 1
21+
// var movingIdx = index + 1
22+
// while movingIdx < strArr.count, dict[strArr[movingIdx]] ?? 0 < 1 {
23+
// dict[strArr[movingIdx]] = 1
24+
// count += 1
25+
// movingIdx += 1
26+
// }
27+
// maxCount = count > maxCount ? count : maxCount
28+
// }
29+
// return maxCount
30+
// }
31+
// 14
732
func lengthOfLongestSubstring(_ s: String) -> Int {
8-
guard s.count > 0 else {
9-
return 0
10-
}
11-
12-
var maxCount = 1
13-
if s.count == 1 {
14-
return maxCount
15-
}
16-
let strArr = Array(s) // Key: convert string to array
17-
for (index, char) in strArr.enumerated() {
18-
var dict: [Character : Int] = [:]
19-
var count = 1
20-
dict[char] = 1
21-
var movingIdx = index + 1
22-
while movingIdx < strArr.count, dict[strArr[movingIdx]] ?? 0 < 1 {
23-
dict[strArr[movingIdx]] = 1
33+
let arr = Array(s)
34+
var dict = [Character : Int]() // [char : idx]
35+
var maxCount = 0
36+
var count = 0
37+
for idx in 0..<arr.count {
38+
if dict[arr[idx]] == nil {
2439
count += 1
25-
movingIdx += 1
40+
dict[arr[idx]] = idx
41+
} else {
42+
let startIdx = dict[arr[idx]]! + 1
43+
dict[arr[idx]] = idx
44+
for key in dict.keys {
45+
if dict[key]! < startIdx {
46+
dict[key] = nil
47+
}
48+
}
49+
count = idx - startIdx + 1
2650
}
27-
maxCount = count>maxCount? count : maxCount
51+
maxCount = max(count,maxCount)
2852
}
2953
return maxCount
3054
}
@@ -38,12 +62,18 @@ class Tests: XCTestCase {
3862
let expected = 3
3963
XCTAssertEqual(solution.lengthOfLongestSubstring(sample), expected)
4064
}
41-
65+
4266
func testSample2() {
4367
let sample = "abcabcbb"
4468
let expected = 3
4569
XCTAssertEqual(solution.lengthOfLongestSubstring(sample), expected)
4670
}
71+
72+
func testSample3() {
73+
let sample = "pwwkew"
74+
let expected = 3
75+
XCTAssertEqual(solution.lengthOfLongestSubstring(sample), expected)
76+
}
4777
}
4878

4979
Tests.defaultTestSuite.run()

‎Medium/0005-LongestPalindromicSubstring.playground/Contents.swift‎

Lines changed: 10 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -11,32 +11,26 @@ class Solution {
1111
var strArr = Array(s)
1212

1313
while length > 0 {
14-
for i in 0...s.count-length {
15-
var left = i
16-
var right = i+length-1
17-
18-
if right >= strArr.count {
19-
break
20-
}
21-
14+
for i in 0...strArr.count-length {
2215
var isPalindrome = true
23-
while left < right {
24-
if strArr[left] != strArr[right] {
16+
var left = i
17+
var right = left + length - 1
18+
while right > left {
19+
if strArr[left] == strArr[right] {
20+
left += 1
21+
right -= 1
22+
} else {
2523
isPalindrome = false
2624
break
2725
}
28-
29-
left += 1
30-
right -= 1
3126
}
32-
3327
if isPalindrome {
3428
return String(strArr[i..<i+length])
3529
}
3630
}
3731
length -= 1
3832
}
39-
return String(strArr[0])
33+
return ""
4034
}
4135
}
4236

@@ -60,7 +54,7 @@ class Tests: XCTestCase {
6054
let expected = "a"
6155
XCTAssertEqual(s.longestPalindrome(input), expected)
6256
}
63-
57+
6458
func testSample4() {
6559
let input = "abcda"
6660
let expected = "a"
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1+
// Leetcode: https://leetcode.com/problems/flatten-binary-tree-to-linked-list/
2+
3+
import XCTest
4+
5+
public class TreeNode {
6+
public var val: Int
7+
public var left: TreeNode?
8+
public var right: TreeNode?
9+
public init(_ val: Int) {
10+
self.val = val
11+
self.left = nil
12+
self.right = nil
13+
}
14+
}
15+
16+
class Solution {
17+
func flatten(_ root: TreeNode?) {
18+
19+
}
20+
}
21+
22+
class Tests: XCTestCase {
23+
let s = Solution()
24+
25+
func testSample1() {
26+
let input = convertArrToTree([1, 2, 5, 3, 4, nil, 6])
27+
}
28+
29+
private func convertArrToTree(_ arr: [Int?]) -> TreeNode? {
30+
guard arr.count > 0 else {
31+
return nil
32+
}
33+
let root = TreeNode(arr[0]!)
34+
convert(0, root, arr)
35+
return root
36+
}
37+
38+
private func convert(_ index: Int, _ root: TreeNode?, _ arr: [Int?]) {
39+
guard let root = root, index*2 + 2 < arr.count else { return }
40+
41+
if let leftVal = arr[index*2+1] {
42+
root.left = TreeNode(leftVal)
43+
convert(index*2+1, root.left, arr)
44+
}
45+
46+
if let rightVal = arr[index*2+2] {
47+
root.right = TreeNode(rightVal)
48+
convert(index*2+2, root.right, arr)
49+
}
50+
}
51+
}
52+
53+
Tests.defaultTestSuite.run()
Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,4 @@
1+
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
2+
<playground version='5.0' target-platform='tvos' executeOnSourceChanges='false'>
3+
<timeline fileName='timeline.xctimeline'/>
4+
</playground>

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