diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000..d79841e
Binary files /dev/null and b/.DS_Store differ
diff --git a/HWFrom1-17-16(Lists and Sorts).playground/Contents.swift b/HWFrom1-17-16(Lists and Sorts).playground/Contents.swift
index 13cc14e..de72e14 100644
--- a/HWFrom1-17-16(Lists and Sorts).playground/Contents.swift	
+++ b/HWFrom1-17-16(Lists and Sorts).playground/Contents.swift	
@@ -11,16 +11,269 @@ Work on your solutions here.
 
 Link: https://docs.google.com/document/d/1INvOynuggw69yLRNg3y-TPwBiYb3lQZQiFUOxZKBwsY/edit#heading=h.za36ai6n5fth
 
-1) 
+*/
 
 
+// 1) Given a partially filled in Sudoku board and a set of coordinates in that board pointing to an empty square, write a function that returns a list containing all numbers that the empty square could be.
 
-2) 
+func getValidNumbersCameron(sudokuBoard:[[Int?]], row:Int, col:Int) -> [Int] {
+    var valid: Set<Int> = [1, 2, 3, 4, 5, 6, 7, 8, 9]
+    
+    for c in 0..<sudokuBoard[row].count {
+        if c == col {
+            continue
+        }
+        if let value = sudokuBoard[row][c] {
+            valid.remove(value)
+        }
+    }
+    
+    for r in 0..<sudokuBoard.count {
+        if r == row {
+            continue
+        }
+        if let value = sudokuBoard[r][col] {
+            valid.remove(value)
+        }
+    }
+    let sqRow = row / 3
+    let sqCol = col / 3
+    
+    for r in sqRow..<(sqRow + 3) {
+        for c in sqCol..<(sqCol + 3) {
+            if r == row && c == col {
+                continue
+            }
+            if let value = sudokuBoard [r][c] {
+                valid.remove(value)
+            }
+        }
+    }
+    // Turn the set to into an Array
+    return Array<Int>(valid)
+}
 
 
 
-3)
 
 
+func getAllColArrayIndexRefactored(paramCol: Int, board: [[Int]]) -> [String: [Int]] {
+    // grab all the index Array that are associated with col
+    let col = paramCol-1
+    var xArray = [Int]()
+    let numberOfColBox = Int(sqrt(Double(board.count)))
+    var xNumber = (col)/numberOfColBox
+    for _ in 0..<numberOfColBox - 1 {
+        xArray.append(xNumber)
+        xNumber += numberOfColBox
+        
+    }
+    
+    var xArrayAtIndex = [Int]()
+    var n = Int()
+    if (col % numberOfColBox == 0) {
+        n = 0
+    } else if (col % numberOfColBox == 1) {
+        n = 1
+    } else {
+        n = 2
+    }
+    for _ in 0..<numberOfColBox - 1 {
+        xArrayAtIndex.append(n)
+        n += numberOfColBox
+    }
+    return ["sudokuSmallBox": xArray, "indexNumber":xArrayAtIndex]
+}
+
+
+func getAllRowArrayIndexRefactored(paramRow: Int, board: [[Int]]) -> [String: [Int]] {
+    // grab all the index Array that are associated with row
+    let row = paramRow - 1
+    var yArray = [Int]()
+    let numberOfRowBox = Int(sqrt(Double(board.count)))
+    var yNumber = row / numberOfRowBox
+    
+    for _ in 0..<numberOfRowBox - 1 {
+        yArray.append(yNumber)
+        yNumber += 1
+    }
+    
+    // grall all the index number that are row Array
+    var yArrayAtIndex = [Int]()
+    var n = Int()
+    if(row % numberOfRowBox == 0){
+        n = 0
+    } else if (row % numberOfRowBox == 1) {
+        n = 3
+    } else {
+        n = 6
+    }
+    
+    for _ in 0..<numberOfRowBox - 1 {
+        yArrayAtIndex.append(n)
+        n += 1
+    }
+    
+    return ["sudokuSmallBox":yArray, "indexNumber":yArrayAtIndex]
+}
+
+
+
+func getAllColArrayIndex(paramCol: Int) -> [String: [Int]] {
+    // grab all the index Array that are associated with col
+    let col = paramCol-1
+    var xArray = [Int]()
+    var xNumber = (col)/3
+    xArray.append(xNumber)
+    xNumber += 3
+    xArray.append(xNumber)
+    xNumber += 3
+    xArray.append(xNumber)
+    var xArrayAtIndex = [Int]()
+    if (col % 3 == 0) {
+        xArrayAtIndex.appendContentsOf([0,3,6])
+    } else if (col % 3 == 1) {
+        xArrayAtIndex.appendContentsOf([1,4,7])
+    } else {
+        xArrayAtIndex.appendContentsOf([2,5,8])
+    }
+    
+    return ["sudokuSmallBox": xArray, "indexNumber":xArrayAtIndex]
+}
+
+func getAllRowArrayIndex(paramRow: Int) -> [String: [Int]] {
+    // grab all the index Array that are associated with row
+    let row = paramRow - 1
+    var yArray = [Int]()
+    var yNumber = (row)/3
+    yArray.append(yNumber)
+    yNumber += 1
+    yArray.append(yNumber)
+    yNumber += 1
+    yArray.append(yNumber)
+    
+    // grall all the index number that are row Array
+    var yArrayAtIndex = [Int]()
+    if(row % 3 == 0){
+        yArrayAtIndex.appendContentsOf([0,1,2])
+    } else if (row % 3 == 1) {
+        yArrayAtIndex.appendContentsOf([3,4,5])
+    } else {
+        yArrayAtIndex.appendContentsOf([6,7,8])
+    }
+    
+    return ["sudokuSmallBox":yArray, "indexNumber":yArrayAtIndex]
+}
+
+func getValidNumbers(sudokuBoard: [[Int]], row: Int, col: Int) -> Set<Int>{
+    let colDictionary = getAllColArrayIndexRefactored(col, board: sudokuBoard)
+//    let rowDictionary = getAllRowArrayIndexRefactored(row, board: sudokuBoard)
+//    let colDictionary = getAllColArrayIndex(col)
+
+    let rowDictionary = getAllRowArrayIndex(row)
+    
+    var colValue = [Int]()
+    for i in colDictionary["sudokuSmallBox"]! {
+        for j in colDictionary["indexNumber"]! {
+            colValue.append(sudokuBoard[i][j])
+        }
+    }
+    
+    var rowValue = [Int]()
+    for i in rowDictionary["sudokuSmallBox"]! {
+        for j in rowDictionary["indexNumber"]! {
+            rowValue.append(sudokuBoard[i][j])
+        }
+    }
+    
+    let combinedRowColValue = Set(colValue).union(Set(rowValue))
+    let completeNumber = Set([0,1,2,3,4,5,6,7,8,9])
+    
+    return completeNumber.subtract(combinedRowColValue)
+}
+
+let sampleInput =   [[5,0,8,9,0,0,0,0,0],
+                    [0,7,3,6,0,0,9,0,8],
+                    [1,9,0,4,0,8,0,3,5],
+                    [0,7,0,0,0,2,0,1,0],
+                    [0,0,0,0,0,0,0,0,0],
+                    [0,6,0,9,0,0,0,8,0],
+                    [1,9,0,2,0,3,0,8,7],
+                    [3,0,6,0,0,7,1,9,0],
+                    [0,0,0,0,0,9,3,0,4]]
+
+let sampleInputCameron: [[Int?]] =   [[5,0,8,9,0,0,0,0,0],
+    [0,7,3,6,0,0,9,0,8],
+    [1,9,0,4,0,8,0,3,5],
+    [0,7,0,0,0,2,0,1,0],
+    [0,0,0,0,0,0,0,0,0],
+    [0,6,0,9,0,0,0,8,0],
+    [1,9,0,2,0,3,0,8,7],
+    [3,0,6,0,0,7,1,9,0],
+    [0,0,0,0,0,9,3,0,4]]
+
+getValidNumbers(sampleInput, row: 4, col: 4)
+getValidNumbersCameron(sampleInputCameron, row: 4, col: 4)
+
+
+// 2) rotate a matrix by ninety degrees
+//      Input: matrix:[[Int]]
+//      Output: matrix: [[Int]]
+//
+//      Sample Input: [[1,2,3,4],
+//                      [5,6,7,8],
+//                      [9,0,1,2],
+//                      [3,4,5,6]]
+//
+//      Sample Output: [[3,9,5,1],
+//                      [4,0,6,2],
+//                      [5,1,7,3],
+//                      [6,2,8,4]]
+
+func rotateMatrixNinetyDegree(matrix: [[Int]]) -> [[Int]] {
+    var rotatedMatrix = [[Int]]()
+    for i in 0..<matrix[0].count {
+        var rowMatrix = [Int]()
+        for j in 0..<matrix.count {
+            rowMatrix.insert(matrix[j][i], atIndex: 0)
+        }
+        rotatedMatrix.append(rowMatrix)
+    }
+    
+    return rotatedMatrix
+}
+
+let matrix = [[1,2,3,4],
+            [5,6,7,8],
+            [9,0,1,2],
+            [3,4,5,6]]
+rotateMatrixNinetyDegree(matrix)
+
+
+
+
+// 3) Design an optimal algorithm for sorting four elements A, B, C, and D. By optimal, I mean one that sorts using the minimum number of comparisons. Hint: you may want to start by putting the first two items in order and the last two items in order... that takes two comparisons. How many more comparisons do you need to find the minimum element? The maximum? Once you’ve found the min and max, what if any additional comparisons are needed?
+
+
+// Once the the first two and the last two are in order then compare the C element with the B element. If C element is greater than B element then all four elements are in order. if not then compare C with A element, if C < A then insert C before A otherwise after A.
+
+func mySort(value: [Int]) -> [Int] {
+    var left = value[0...1]
+    if left[0] > left [1] {
+        let t = left[0]
+        left[0] = left[1]
+        left[1] = t
+    }
+    
+    var right = value[2...4]
+    if right[0] > right [1] {
+        let t = right[1]
+        right[0] = right[1]
+        right[1] = t
+    }
+    // 1 3
+    // 2 4
+    
+    return[]
+}
 
-*/
diff --git a/HWFrom1-24(Recursion).playground/Contents.swift b/HWFrom1-24(Recursion).playground/Contents.swift
index 1c44504..d341065 100644
--- a/HWFrom1-24(Recursion).playground/Contents.swift
+++ b/HWFrom1-24(Recursion).playground/Contents.swift
@@ -1,3 +1,5 @@
+import Foundation
+
 /*
 
 
@@ -10,16 +12,47 @@ Homework link: https://docs.google.com/document/d/1INvOynuggw69yLRNg3y-TPwBiYb3l
 
 
 //Question 1
+func fib(firstNumber: Int, secondNumber: Int, n: Int) -> Int {
+    var previousNumber1 = firstNumber
+    var previousNumber2 = secondNumber
+    var nth = 0
+    for _ in 0..<n - 2 {
+        nth = previousNumber1 + previousNumber2
+        previousNumber1 = previousNumber2
+        previousNumber2 = nth
+    }
+    return nth
+}
 
-
-
-
+//print(fib(1, secondNumber: 1, n: 5))
 
 
 //Question 2
 
+var stepNum = 0
+func tryStep() -> Int {
+    let stepCount = Int(arc4random_uniform(3)) - 1
+    stepNum += stepCount;
+    switch(stepCount) {
+    case -1: print("Ouch \(stepNum)")
+    case 1: print("Yay  \(stepNum)")
+    default: print("Beep \(stepNum)")
+    }
+    return stepCount
+}
+
+func stepUp() {
+    let didTryStep = tryStep()
+    if didTryStep == 0 {
+        stepUp()
+    } else if didTryStep == -1 {
+        stepUp()
+        stepUp()
+    }
+}
+
+stepUp()
+
+//Question 3
 
 
-
-
-//Question 3
\ No newline at end of file
diff --git a/HWfrom1-09-16(SwiftIntro).playground/Contents.swift b/HWfrom1-09-16(SwiftIntro).playground/Contents.swift
index 488e9ed..67d9256 100644
--- a/HWfrom1-09-16(SwiftIntro).playground/Contents.swift
+++ b/HWfrom1-09-16(SwiftIntro).playground/Contents.swift
@@ -10,14 +10,78 @@ Use the link here to get the questions.  Then code your solutions below.  If it
 
 https://docs.google.com/document/d/1DQ2aCJ_yUZtazzCfb0PaS81bg61V2ZOSxpABh981xSo/edit
 
+*/
 
-1)
-
-2)
+// 1) Given an integer N, there is a list of size N-1 that is missing one number from 1 - N(inclusive). Find that number.
+func findTheMissingNumberFromAnArray(numberList:[Int], totalN: Int) -> Int {
+    var totalSumOfAnArray = 0
+    var totalSumOfNonMissingArray = 0
+    
+    for i in 1...totalN {
+        totalSumOfNonMissingArray += i
+    }
+    for i in 1...numberList.count {
+        totalSumOfAnArray += i
+    }
+    
+    return totalSumOfNonMissingArray - totalSumOfAnArray
+}
 
-3)
+// 3)Given two lists, find the smallest value that exists in both lists.
+// L1 = [1,2,5,9]
+// L2 = [9, 20 , 5]
+func smallestValueFromTwoArray(list1: [Int], list2: [Int]) -> Int {
+    let sortedList1 = list1.sort({$0 < $1})
+    let sortedList2 = list2.sort({$0 < $1})
+    if sortedList1.first > sortedList2.first {
+        return sortedList2.first!
+    } else {
+        return sortedList1.first!
+    }
+}
 
-4)
+// 4) Check to see if an integer is a palindrome don’t use casting
+func isIntegerPalindrome(number: Int) -> Bool {
+    var digits = 1
+    var tens = 10
+    while (number / tens > 0) {
+        digits += 1
+        tens *= 10
+    }
+    
+    var moduleOfTen = 10
+    for i in 0...digits {
+        var prevBackEndNumber : Int?
+        var backEndNum = 0
+        if (prevBackEndNumber != nil) {
+            backEndNum = number % moduleOfTen
+            backEndNum -= prevBackEndNumber!
+        } else {
+         backEndNum = number % moduleOfTen
+        }
+        
+        
+        var frontEndNum = 0
+        var prevFrontEndNumber : Int?
+        if (prevFrontEndNumber != nil){
+            frontEndNum = number / Int(pow(Double(10), Double(digits - i)))
+            frontEndNum -= prevFrontEndNumber!
+        } else {
+            frontEndNum = number / Int(pow(Double(10), Double(digits - i)))
+        }
+        
+        if (frontEndNum != backEndNum){
+            return false
+        } else {
+            moduleOfTen *= 10
+            prevBackEndNumber = backEndNum
+            prevFrontEndNumber = frontEndNum
+        }
+    }
+    print(digits)
+    return true
+}
+let num = 12321
+isIntegerPalindrome(num)
 
 
-*/
diff --git a/HWfrom1-10-016(BigO).playground/Contents.swift b/HWfrom1-10-016(BigO).playground/Contents.swift
index 2040d38..3c580e8 100644
--- a/HWfrom1-10-016(BigO).playground/Contents.swift
+++ b/HWfrom1-10-016(BigO).playground/Contents.swift
@@ -12,8 +12,23 @@ https://docs.google.com/document/d/1aF1imJUVahCSJAuN1OEm5lQXwpSFaAmVmAETKMM6PLQ/
 
 
 1)
+    a) ANS = 160 ps
+    b) O(n^2)
+    c) O(n^2)
+
+2) a) n^4 , n^3 , n^2
+    b) O(n!)
+    c) 
+    func isDuplication -> Bool {
+    let friendsArray = ["mike","joe","hello"]
+    let unique = Array(Set(friendsArray))
+    if  (friendsAray == unique) {
+    return false
+    } else {
+    return true
+    }
+    }
 
-2)
 
 3)
 
diff --git a/HWfrom1-14-16(Logic+Discrete_Math).playground/Contents.swift b/HWfrom1-14-16(Logic+Discrete_Math).playground/Contents.swift
index bc0df91..d8681ed 100644
--- a/HWfrom1-14-16(Logic+Discrete_Math).playground/Contents.swift
+++ b/HWfrom1-14-16(Logic+Discrete_Math).playground/Contents.swift
@@ -10,20 +10,57 @@ var str = "Hello, playground"
 Question 1: https://www.hackerrank.com/challenges/minimum-draws
 
 Copy and paste your code:
+*/
+func maxDraw (sock: Int) -> Int {
+    if sock == 1 {
+        return 2
+    } else {
+        return sock/2 + 1
+    }
+}
+/*
+What is the big O runtime of your code?: O(1)
+*/
+
 
-What is the big O runtime of your code?:
 
+
+
+/*
 Question 2: https://www.hackerrank.com/challenges/handshake
 
 Copy and paste your code:
+*/
+func totalHandshakes(people: Int) -> Int {
+    
+    return (people - 1) * (people)/2
+}
+/*
+What is the big O runtime of your code?: O(1)
+*/
+
 
-What is the big O runtime of your code?:
 
+
+/*
 Question 3: https://www.hackerrank.com/challenges/connecting-towns
 
 Copy and paste your code:
+*/
 
-What is the big O runtime of your code?:
+func totalPath(towns:[Int]) -> Int {
+    if (towns.count > 0) {
+        var totalPath = 1
+        for n in towns {
+            totalPath *= n
+        }
+        return totalPath
+    } else {
+        return 0
+    }
+    
+}
 
+/*
+What is the big O runtime of your code?:
 */
-
diff --git a/calebRecursionHW/calebRecursionHW.xcodeproj/project.pbxproj b/calebRecursionHW/calebRecursionHW.xcodeproj/project.pbxproj
new file mode 100644
index 0000000..672920a
--- /dev/null
+++ b/calebRecursionHW/calebRecursionHW.xcodeproj/project.pbxproj
@@ -0,0 +1,246 @@
+// !$*UTF8*$!
+{
+	archiveVersion = 1;
+	classes = {
+	};
+	objectVersion = 46;
+	objects = {
+
+/* Begin PBXBuildFile section */
+		D48F562E1C5AD57D00F290BF /* main.swift in Sources */ = {isa = PBXBuildFile; fileRef = D48F562D1C5AD57D00F290BF /* main.swift */; };
+/* End PBXBuildFile section */
+
+/* Begin PBXCopyFilesBuildPhase section */
+		D48F56281C5AD57D00F290BF /* CopyFiles */ = {
+			isa = PBXCopyFilesBuildPhase;
+			buildActionMask = 2147483647;
+			dstPath = /usr/share/man/man1/;
+			dstSubfolderSpec = 0;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 1;
+		};
+/* End PBXCopyFilesBuildPhase section */
+
+/* Begin PBXFileReference section */
+		D48F562A1C5AD57D00F290BF /* calebRecursionHW */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = calebRecursionHW; sourceTree = BUILT_PRODUCTS_DIR; };
+		D48F562D1C5AD57D00F290BF /* main.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = main.swift; sourceTree = "<group>"; };
+/* End PBXFileReference section */
+
+/* Begin PBXFrameworksBuildPhase section */
+		D48F56271C5AD57D00F290BF /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXFrameworksBuildPhase section */
+
+/* Begin PBXGroup section */
+		D48F56211C5AD57D00F290BF = {
+			isa = PBXGroup;
+			children = (
+				D48F562C1C5AD57D00F290BF /* calebRecursionHW */,
+				D48F562B1C5AD57D00F290BF /* Products */,
+			);
+			sourceTree = "<group>";
+		};
+		D48F562B1C5AD57D00F290BF /* Products */ = {
+			isa = PBXGroup;
+			children = (
+				D48F562A1C5AD57D00F290BF /* calebRecursionHW */,
+			);
+			name = Products;
+			sourceTree = "<group>";
+		};
+		D48F562C1C5AD57D00F290BF /* calebRecursionHW */ = {
+			isa = PBXGroup;
+			children = (
+				D48F562D1C5AD57D00F290BF /* main.swift */,
+			);
+			path = calebRecursionHW;
+			sourceTree = "<group>";
+		};
+/* End PBXGroup section */
+
+/* Begin PBXNativeTarget section */
+		D48F56291C5AD57D00F290BF /* calebRecursionHW */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = D48F56311C5AD57D00F290BF /* Build configuration list for PBXNativeTarget "calebRecursionHW" */;
+			buildPhases = (
+				D48F56261C5AD57D00F290BF /* Sources */,
+				D48F56271C5AD57D00F290BF /* Frameworks */,
+				D48F56281C5AD57D00F290BF /* CopyFiles */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = calebRecursionHW;
+			productName = calebRecursionHW;
+			productReference = D48F562A1C5AD57D00F290BF /* calebRecursionHW */;
+			productType = "com.apple.product-type.tool";
+		};
+/* End PBXNativeTarget section */
+
+/* Begin PBXProject section */
+		D48F56221C5AD57D00F290BF /* Project object */ = {
+			isa = PBXProject;
+			attributes = {
+				LastSwiftUpdateCheck = 0720;
+				LastUpgradeCheck = 0720;
+				ORGANIZATIONNAME = "Jason Wang";
+				TargetAttributes = {
+					D48F56291C5AD57D00F290BF = {
+						CreatedOnToolsVersion = 7.2;
+					};
+				};
+			};
+			buildConfigurationList = D48F56251C5AD57D00F290BF /* Build configuration list for PBXProject "calebRecursionHW" */;
+			compatibilityVersion = "Xcode 3.2";
+			developmentRegion = English;
+			hasScannedForEncodings = 0;
+			knownRegions = (
+				en,
+			);
+			mainGroup = D48F56211C5AD57D00F290BF;
+			productRefGroup = D48F562B1C5AD57D00F290BF /* Products */;
+			projectDirPath = "";
+			projectRoot = "";
+			targets = (
+				D48F56291C5AD57D00F290BF /* calebRecursionHW */,
+			);
+		};
+/* End PBXProject section */
+
+/* Begin PBXSourcesBuildPhase section */
+		D48F56261C5AD57D00F290BF /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				D48F562E1C5AD57D00F290BF /* main.swift in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXSourcesBuildPhase section */
+
+/* Begin XCBuildConfiguration section */
+		D48F562F1C5AD57D00F290BF /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				CODE_SIGN_IDENTITY = "-";
+				COPY_PHASE_STRIP = NO;
+				DEBUG_INFORMATION_FORMAT = dwarf;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_TESTABILITY = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_DYNAMIC_NO_PIC = NO;
+				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_OPTIMIZATION_LEVEL = 0;
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=1",
+					"$(inherited)",
+				);
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				MACOSX_DEPLOYMENT_TARGET = 10.11;
+				MTL_ENABLE_DEBUG_INFO = YES;
+				ONLY_ACTIVE_ARCH = YES;
+				SDKROOT = macosx;
+				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+			};
+			name = Debug;
+		};
+		D48F56301C5AD57D00F290BF /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				CODE_SIGN_IDENTITY = "-";
+				COPY_PHASE_STRIP = NO;
+				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
+				ENABLE_NS_ASSERTIONS = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				MACOSX_DEPLOYMENT_TARGET = 10.11;
+				MTL_ENABLE_DEBUG_INFO = NO;
+				SDKROOT = macosx;
+			};
+			name = Release;
+		};
+		D48F56321C5AD57D00F290BF /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				PRODUCT_NAME = "$(TARGET_NAME)";
+			};
+			name = Debug;
+		};
+		D48F56331C5AD57D00F290BF /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				PRODUCT_NAME = "$(TARGET_NAME)";
+			};
+			name = Release;
+		};
+/* End XCBuildConfiguration section */
+
+/* Begin XCConfigurationList section */
+		D48F56251C5AD57D00F290BF /* Build configuration list for PBXProject "calebRecursionHW" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				D48F562F1C5AD57D00F290BF /* Debug */,
+				D48F56301C5AD57D00F290BF /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		D48F56311C5AD57D00F290BF /* Build configuration list for PBXNativeTarget "calebRecursionHW" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				D48F56321C5AD57D00F290BF /* Debug */,
+				D48F56331C5AD57D00F290BF /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+		};
+/* End XCConfigurationList section */
+	};
+	rootObject = D48F56221C5AD57D00F290BF /* Project object */;
+}
diff --git a/calebRecursionHW/calebRecursionHW.xcodeproj/project.xcworkspace/contents.xcworkspacedata b/calebRecursionHW/calebRecursionHW.xcodeproj/project.xcworkspace/contents.xcworkspacedata
new file mode 100644
index 0000000..18b8165
--- /dev/null
+++ b/calebRecursionHW/calebRecursionHW.xcodeproj/project.xcworkspace/contents.xcworkspacedata
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "self:calebRecursionHW.xcodeproj">
+   </FileRef>
+</Workspace>
diff --git a/calebRecursionHW/calebRecursionHW/main.swift b/calebRecursionHW/calebRecursionHW/main.swift
new file mode 100644
index 0000000..2f54b40
--- /dev/null
+++ b/calebRecursionHW/calebRecursionHW/main.swift
@@ -0,0 +1,38 @@
+//
+//  main.swift
+//  calebRecursionHW
+//
+//  Created by Jason Wang on 1/28/16.
+//  Copyright © 2016 Jason Wang. All rights reserved.
+//
+
+import Foundation
+
+
+func findFile(name: String, atPath: String) -> String {
+    let fileManager = NSFileManager.defaultManager()
+    let contents = try! fileManager.contentsOfDirectoryAtPath(atPath)
+    for fileOrDir in contents {
+        var isDir = ObjCBool(false);
+        let fullPath = atPath + "/" + fileOrDir
+        let exists = fileManager.fileExistsAtPath(fullPath, isDirectory: &isDir)
+        if exists && Bool(isDir) {
+            // YOUR CODE HERE
+            print("DIR: " + fileOrDir)
+            let result = findFile(name, atPath: fullPath)
+            if result != "NOT FOUND" {
+                return result
+            }
+        } else if exists {
+            // YOUR CODE HERE
+                if fileOrDir == name {
+                    return "FOUND" + "FILE: " + fullPath
+                }
+        } else {
+            print("NEITHER: " + fileOrDir)
+        }
+    }
+    return "NOT FOUND"
+}
+
+print(findFile("20160112JasonWang.pdf", atPath: "/Users/jasonwang/Documents"))