Added new solutions

Michael Ho · Michael Ho · commit 9aabad5537a0 · 2018-09-18T22:42:58.000-04:00
diff --git a/Easy/0027-RemoveElement.playground/Contents.swift b/Easy/0027-RemoveElement.playground/Contents.swift
@@ -0,0 +1,16 @@
+// LeetCode: https://leetcode.com/problems/remove-element/description/
+
+class Solution{
+ func removeElement(_ nums: inout [Int], _ val: Int) -> Int{
+ nums = nums.filter{$0 != val }
+ return nums.count
+ }
+}
+
+let solution = Solution()
+var arr1 = [3,2,2,3]
+print("\(solution.removeElement(&arr1, 3))") // 2
+print(arr1)
+var arr2 = [0,1,2,2,3,0,4,2]
+print("\(solution.removeElement(&arr2, 2))") // 5
+print(arr2)
diff --git a/Easy/0027-RemoveElement.playground/contents.xcplayground b/Easy/0027-RemoveElement.playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Easy/0028-ImplementstrStr().playground/Contents.swift b/Easy/0028-ImplementstrStr().playground/Contents.swift
@@ -0,0 +1,26 @@
+// LeetCode: https://leetcode.com/problems/implement-strstr/description/
+
+class Solution{
+ func strStr(_ haystack: String, _ needle: String) -> Int{
+ var index = -1
+ guard needle.count > 0 else{
+ return 0
+ }
+ var nArr = Array(needle)
+ var hArr = Array(haystack)
+ for (idx, c) in hArr.enumerated(){
+ if c == nArr[0], idx + (nArr.count) <= hArr.count, String(hArr[idx..<idx + (nArr.count)]) == needle{
+ index = idx
+ break
+ }
+ }
+ return index
+ }
+}
+
+let solution = Solution()
+print(solution.strStr("hello", "ll")) // 2
+print(solution.strStr("aaa", "aa")) // 0
+print(solution.strStr("aaa", "a")) // 0
+print(solution.strStr("", "")) // 0
+print(solution.strStr("a", "a")) // 0
diff --git a/Easy/0028-ImplementstrStr().playground/contents.xcplayground b/Easy/0028-ImplementstrStr().playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Easy/0035-SearchInsertPosition.playground/Contents.swift b/Easy/0035-SearchInsertPosition.playground/Contents.swift
@@ -0,0 +1,21 @@
+// LeetCode: https://leetcode.com/problems/search-insert-position/description/
+
+class Solution{
+ func searchInsert(_ nums: [Int], _ target: Int) -> Int{
+ var output = 0
+ for i in 0..<nums.count{
+ if target > nums[i]{
+ output = i + 1
+ } else if target == nums[i]{
+ output = i
+ }
+ }
+ return output
+ }
+}
+
+let solution = Solution()
+print(solution.searchInsert([1,3,5,6], 5)) // 2
+print(solution.searchInsert([1,3,5,6], 2)) // 1
+print(solution.searchInsert([1,3,5,6], 7)) // 4
+print(solution.searchInsert([1,3,5,6], 0)) // 0
diff --git a/Easy/0035-SearchInsertPosition.playground/contents.xcplayground b/Easy/0035-SearchInsertPosition.playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Easy/0053-MaximumSubarray.playground/Contents.swift b/Easy/0053-MaximumSubarray.playground/Contents.swift
@@ -0,0 +1,22 @@
+// LeetCode: https://leetcode.com/problems/maximum-subarray/description/
+
+class Solution{
+ func maxSubArray(_ nums: [Int]) -> Int{
+ var max = nums[0]
+ for i in 0..<nums.count{
+ var current = nums[i]
+ max = current > max ? current : max
+ var index = i + 1
+ while index < nums.count{
+ current += nums[index]
+ max = current > max ? current : max
+ index += 1
+ }
+ }
+ return max
+ }
+}
+
+let solution = Solution()
+print(solution.maxSubArray([-2,1,-3,4,-1,2,1,-5,4])) // 6
+print(solution.maxSubArray([-2,1])) // 1
diff --git a/Easy/0053-MaximumSubarray.playground/contents.xcplayground b/Easy/0053-MaximumSubarray.playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Medium/0011-ContainerWithMostWater.playground/Contents.swift b/Medium/0011-ContainerWithMostWater.playground/Contents.swift
@@ -0,0 +1,25 @@
+// LeetCode: https://leetcode.com/problems/container-with-most-water/description/
+
+class Solution{
+ func maxArea(_ height: [Int]) -> Int{
+ var area = 0
+ var start = 0
+ var end = height.count - 1
+ while start < end{
+ let areaH = min(height[start], height[end])
+ let width = end - start
+ if areaH * width > area{
+ area = areaH * width
+ }
+ if height[start] < height[end]{
+ start += 1
+ } else{
+ end -= 1
+ }
+ }
+ return area
+ }
+}
+
+let solution = Solution()
+print("\(solution.maxArea([1,8,6,2,5,4,8,3,7]))") // 49
diff --git a/Medium/0011-ContainerWithMostWater.playground/contents.xcplayground b/Medium/0011-ContainerWithMostWater.playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Medium/0015-3Sum.playground/Contents.swift b/Medium/0015-3Sum.playground/Contents.swift
@@ -6,33 +6,31 @@ class Solution{
 guard nums.count >= 3 else{
 return []
 }
- nums.sorted()
- var idxArr: [[Int]] = []
- var pair: [[Int]] = []
- var num1: [Int] = []
- for idx1 in 0..<nums.count{
- if num1.contains(nums[idx1]){
- break
+ let sort = nums.sorted()
+ var output: [[Int]] = []
+ for i in 0..<sort.count - 2{
+ if i > 0, sort[i] == sort[i-1]{
+ continue
 }
- num1.append(nums[idx1])
- for idx2 in idx1+1..<nums.count{
- if pair.contains([nums[idx1], nums[idx2]].sorted()){
- continue
+ var start = i + 1
+ var end = sort.count - 1
+ while start < end{
+ if sort[i] + sort[start] + sort[end] == 0{
+ output.append([sort[i], sort[start], sort[end]])
+ start += 1
+ end -= 1
+ } else if sort[i] + sort[start] + sort[end] < 0{
+ start += 1
 } else{
- pair.append([nums[idx1], nums[idx2]].sorted())
- idxArr.append([idx1, idx2])
+ end -= 1
 }
- }
- }
- var output: [[Int]] = []
- for i in 0..<nums.count{
- for pair in idxArr{
- if i == pair[0] || i == pair[1]{
+ if start - 1 >= 0 && sort[start] == sort[start - 1]{
+ start += 1
 continue
 }
- 
- if nums[i] + nums[pair[0]] + nums[pair[1]] == 0, !output.contains([nums[i], nums[pair[0]], nums[pair[1]]].sorted()){
- output.append([nums[i], nums[pair[0]], nums[pair[1]]].sorted())
+ if end + 1 < sort.count && sort[end] == sort[end + 1]{
+ end -= 1
+ continue
 }
 }
 }
@@ -68,6 +66,15 @@ print("---------------------------------")
 [-1, 0, 1]
 ]
 */
+print("\(solution.threeSum([-2,0,1,1,2]))")
+/**
+ The solution set is:
+ [
+ [-2,0,2],
+ [-2,1,1]
+ ]
+ */
+print("\(solution.threeSum([1,1,1]))") // [[]]
 let longArray1 = [-2,10,-14,11,5,-4,2,0,-10,-10,5,7,-11,10,-2,-5,2,12,-5,14,-11,-15,-5,12,0,13,8,7,10,6,-9,-15,1,14,11,-9,-13,-10,6,-8,-5,-11,6,-9,14,11,-7,-6,8,3,-7,5,-5,3,2,10,-6,-12,3,11,1,1,12,10,-8,0,8,-5,6,-8,-6,8,-12,-14,7,9,12,-15,-12,-2,-4,-4,-12,6,7,-3,-6,-14,-8,4,4,9,-10,-7,-4,-3,1,11,-1,-8,-12,9,7,-9,10,-1,-14,-1,-8,11,12,-5,-7]
 print(longArray1.count)
 print("\(solution.threeSum(longArray1))") // Test time limit
@@ -76,11 +83,3 @@ let longArray2 = [12,-14,-5,12,-2,9,0,9,-3,-3,-14,-6,-4,13,-11,-8,0,5,-7,-6,-10,
 print(longArray2.count)
 print("\(solution.threeSum(longArray2))") // Test time limit
 print("---------------------------------")
-print("\(solution.threeSum([-2,0,1,1,2]))")
-/**
- The solution set is:
- [
- [-2,0,2],
- [-2,1,1]
- ]
-*/
diff --git a/Medium/0018-4Sum.playground/Contents.swift b/Medium/0018-4Sum.playground/Contents.swift
@@ -0,0 +1,73 @@
+// LeetCode: https://leetcode.com/problems/4sum/description/
+// Difficulty: Medium
+// O(n^3) is acceptable
+
+class Solution{
+ func fourSum(_ nums: [Int], _ target: Int) -> [[Int]]{
+ var output: [[Int]] = []
+ var sortedNums = nums.sorted()
+ for idx1 in 0..<sortedNums.count{
+ for idx2 in (idx1+1)..<sortedNums.count{
+ var start = idx2 + 1
+ var end = sortedNums.count - 1
+ let comp = target - sortedNums[idx1] - sortedNums[idx2]
+ while start < end{
+ if comp == sortedNums[start] + sortedNums[end], !output.contains([sortedNums[idx1], sortedNums[idx2], sortedNums[start], sortedNums[end]]){
+ output.append([sortedNums[idx1], sortedNums[idx2], sortedNums[start], sortedNums[end]])
+ if end - start == 2{
+ start += 1
+ continue
+ }
+ start += 1
+ end -= 1
+ } else if comp > sortedNums[start] + sortedNums[end]{
+ start += 1
+ } else{
+ end -= 1
+ }
+ }
+ }
+ }
+ return output
+ }
+}
+
+let solution = Solution()
+print("\(solution.fourSum([1, 0, -1, 0, -2, 2], 0))")
+/**
+ // Sorted: [-2, -1, 0, 0, 1, 2]
+ [
+ [-1, 0, 0, 1],
+ [-2, -1, 1, 2],
+ [-2, 0, 0, 2]
+ ]
+ */
+print("\(solution.fourSum([-1, 0, -5, -2, -2, -4, 0, 1, -2], -9))")
+/**
+ // Sorted: [-5, -4, -2, -2, -2, -1, 0, 0, 1]
+ [
+ [-5,-4,-1,1],
+ [-5,-4,0,0],
+ [-5,-2,-2,0],
+ [-4,-2,-2,-1]
+ ]
+ */
+print("\(solution.fourSum([0, 0, 0, 0], 0))")
+/**
+ [
+ [0, 0, 0, 0]
+ ]
+ */
+print("\(solution.fourSum([-3,-2,-1,0,0,1,2,3], 0))")
+/**
+ [
+ [-3, -2, 2, 3],
+ [-3, -1, 1, 3],
+ [-3, 0, 0, 3],
+ [-3, 0, 1, 2],
+ [-2, -1, 0, 3],
+ [-2, -1, 1, 2],
+ [-2, 0, 0, 2],
+ [-1, 0, 0, 1]
+ ]
+ */
diff --git a/Medium/0018-4Sum.playground/contents.xcplayground b/Medium/0018-4Sum.playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Medium/0029-DivideTwoIntegers.playground/Contents.swift b/Medium/0029-DivideTwoIntegers.playground/Contents.swift
@@ -0,0 +1,13 @@
+// LeetCode: https://leetcode.com/problems/divide-two-integers/description/
+
+class Solution{
+ func divide(_ dividend: Int, _ divisor: Int) -> Int{
+ var output = dividend / divisor
+ output = output > Int32.max ? Int(Int32.max) : output
+ output = output < Int32.min ? Int(Int32.min) : output
+ return output
+ }
+}
+
+let solution = Solution()
+print(solution.divide(-2147483648, -1)) // 2147483647
diff --git a/Medium/0029-DivideTwoIntegers.playground/contents.xcplayground b/Medium/0029-DivideTwoIntegers.playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Medium/0039-CombinationSum.playground/Contents.swift b/Medium/0039-CombinationSum.playground/Contents.swift
@@ -0,0 +1,47 @@
+// LeetCode: https://leetcode.com/problems/combination-sum/description/
+
+class Solution{
+ func combinationSum(_ candidates: [Int], _ target: Int) -> [[Int]]{
+ guard target > 0 else{
+ return []
+ }
+ var output: [[Int]] = []
+ for start in candidates{
+ var newSeq: [Int] = [start]
+ combinationSum(&output, &newSeq, candidates, target - start)
+ }
+ return output
+ }
+ 
+ func combinationSum(_ output: inout [[Int]], _ sequance: inout [Int], _ candidates: [Int], _ target: Int){
+ if target == 0, !output.contains(sequance.sorted()){
+ output.append(sequance.sorted())
+ return
+ }
+ guard target > 0 else{return }
+ for i in candidates{
+ var temp = sequance
+ temp.append(i)
+ combinationSum(&output, &temp, candidates, target - i)
+ }
+ }
+}
+
+let solution = Solution()
+print(solution.combinationSum([2,3,6,7], 7))
+/**
+ The output should be:
+ [
+ [2,2,3]
+ [7]
+ ]
+ */
+print(solution.combinationSum([2,3,5], 8))
+/**
+ The output should be:
+ [
+ [2,2,2,2]
+ [2,3,3]
+ [3,5]
+ ]
+ */
diff --git a/Medium/0039-CombinationSum.playground/contents.xcplayground b/Medium/0039-CombinationSum.playground/contents.xcplayground
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos'>
+ <timeline fileName='timeline.xctimeline'/>
+</playground>
diff --git a/Medium/0040-CombinationSumII.playground/Contents.swift b/Medium/0040-CombinationSumII.playground/Contents.swift
diff --git a/Medium/0040-CombinationSumII.playground/contents.xcplayground b/Medium/0040-CombinationSumII.playground/contents.xcplayground

-Original file line number
+Diff line change
@@ @@ -0,0 +1,16 @@ @@
 +// LeetCode: https://leetcode.com/problems/remove-element/description/
++
 +classSolution{
 +func removeElement(_ nums:inout[Int], _ val:Int)->Int{
 + nums = nums.filter{ $0 != val }
 +return nums.count
 +}
 +}
++
 +letsolution=Solution()
 +vararr1=[3,2,2,3]
 +print("\(solution.removeElement(&arr1,3))") // 2
 +print(arr1)
 +vararr2=[0,1,2,2,3,0,4,2]
 +print("\(solution.removeElement(&arr2,2))") // 5
 +print(arr2)
-Original file line number
+Diff line change
@@ @@ -0,0 +1,26 @@ @@
 +// LeetCode: https://leetcode.com/problems/implement-strstr/description/
++
 +classSolution{
 +func strStr(_ haystack:String, _ needle:String)->Int{
 +varindex=-1
 +guard needle.count >0else{
 +return0
 +}
 +varnArr=Array(needle)
 +varhArr=Array(haystack)
 +for(idx, c)in hArr.enumerated(){
 +if c ==nArr[0], idx +(nArr.count)<= hArr.count,String(hArr[idx..<idx +(nArr.count)])== needle {
 + index = idx
 +break
 +}
 +}
 +return index
 +}
 +}
++
 +letsolution=Solution()
 +print(solution.strStr("hello","ll")) // 2
 +print(solution.strStr("aaa","aa")) // 0
 +print(solution.strStr("aaa","a")) // 0
 +print(solution.strStr("","")) // 0
 +print(solution.strStr("a","a")) // 0
-Original file line number
+Diff line change
@@ @@ -0,0 +1,21 @@ @@
 +// LeetCode: https://leetcode.com/problems/search-insert-position/description/
++
 +classSolution{
 +func searchInsert(_ nums:[Int], _ target:Int)->Int{
 +varoutput=0
 +foriin0..<nums.count {
 +if target >nums[i]{
 + output = i +1
 +}elseif target ==nums[i]{
 + output = i
 +}
 +}
 +return output
 +}
 +}
++
 +letsolution=Solution()
 +print(solution.searchInsert([1,3,5,6],5)) // 2
 +print(solution.searchInsert([1,3,5,6],2)) // 1
 +print(solution.searchInsert([1,3,5,6],7)) // 4
 +print(solution.searchInsert([1,3,5,6],0)) // 0
-Original file line number
+Diff line change
@@ @@ -0,0 +1,25 @@ @@
 +// LeetCode: https://leetcode.com/problems/container-with-most-water/description/
++
 +classSolution{
 +func maxArea(_ height:[Int])->Int{
 +vararea=0
 +varstart=0
 +varend= height.count -1
 +while start < end {
 +letareaH=min(height[start],height[end])
 +letwidth= end - start
 +if areaH * width > area {
 + area = areaH * width
 +}
 +ifheight[start]<height[end]{
 + start +=1
 +}else{
 + end -=1
 +}
 +}
 +return area
 +}
 +}
++
 +letsolution=Solution()
 +print("\(solution.maxArea([1,8,6,2,5,4,8,3,7]))") // 49