diff --git "a/\355\225\234\352\267\274\354\230\201/.DS_Store" "b/\355\225\234\352\267\274\354\230\201/.DS_Store"
new file mode 100644
index 0000000..bd0491b
Binary files /dev/null and "b/\355\225\234\352\267\274\354\230\201/.DS_Store" differ
diff --git "a/\355\225\234\352\267\274\354\230\201/2\352\260\234\354\235\264\355\225\230\353\241\234\353\213\244\353\245\270\353\271\204\355\212\270_level2.swift" "b/\355\225\234\352\267\274\354\230\201/2\352\260\234\354\235\264\355\225\230\353\241\234\353\213\244\353\245\270\353\271\204\355\212\270_level2.swift"
new file mode 100644
index 0000000..83cac15
--- /dev/null
+++ "b/\355\225\234\352\267\274\354\230\201/2\352\260\234\354\235\264\355\225\230\353\241\234\353\213\244\353\245\270\353\271\204\355\212\270_level2.swift"
@@ -0,0 +1,35 @@
+//220331
+//프로그래머스 [level2] 2개 이하로 다른 비트 문제
+//https://programmers.co.kr/learn/courses/30/lessons/77885
+
+import Foundation
+
+func solution(_ numbers:[Int64]) -> [Int64] {
+    var answer = [Int64]()
+    for n in numbers {
+        var bit = String(Int(n),radix:2).map{String($0)}
+        if bit.last! == "0" {
+            bit[bit.count-1] = "1"
+        } else if let zeroIndex = bit.lastIndex(of:"0"){
+            bit[zeroIndex] = "1"
+            bit[zeroIndex+1] = "0"
+        } else {
+            bit.insert("1",at:0)
+            bit[1] = "0"
+        }
+        answer += [Int64(bit.joined(separator:""),radix:2)!]
+    }
+    return answer
+}
+
+/*
+다른 사람 풀이(이렇게 비트 연산 이용해서)
+
+func solution(_ numbers: [Int64]) -> [Int64] {
+    return numbers.map(f)
+}
+
+func f(_ number: Int64) -> Int64 {
+    return (number | ~number & (number + 1)) & ~((~number & (number + 1)) >> 1)
+}
+*/
\ No newline at end of file
diff --git "a/\355\225\234\352\267\274\354\230\201/\355\201\260\354\210\230\353\247\214\353\223\244\352\270\260_level2.swift" "b/\355\225\234\352\267\274\354\230\201/\355\201\260\354\210\230\353\247\214\353\223\244\352\270\260_level2.swift"
new file mode 100644
index 0000000..1318444
--- /dev/null
+++ "b/\355\225\234\352\267\274\354\230\201/\355\201\260\354\210\230\353\247\214\353\223\244\352\270\260_level2.swift"
@@ -0,0 +1,79 @@
+//220329
+//프로그래머스 [level2] 큰 수 만들기 문제
+//https://programmers.co.kr/learn/courses/30/lessons/42883
+
+//최종!
+import Foundation
+
+func solution(_ number:String, _ k:Int) -> String {
+    let nArr = number.map{String($0)}
+    var answer = [String]() //stack
+    var erase = 0
+    var i = 0
+    while(k>erase){ 
+        if i == nArr.count{
+            answer.removeLast()
+            erase += 1
+        }else if answer.count == 0 || answer.last! >= nArr[i]{
+            answer += [nArr[i]]
+            i += 1
+        } else if answer.last! < nArr[i]{
+            answer.removeLast()
+            erase += 1
+        }
+    }
+    answer += Array(nArr[i...])
+    return answer.joined(separator:"")
+}
+
+
+/*
+func solution(_ number:String, _ k:Int) -> String {
+    var nArr = number.map{String($0)}
+    var erase = 0
+    var i = 0
+    while(k>erase){
+        if i == nArr.count-1 {
+            nArr.removeLast()
+            erase += 1
+        }else if nArr[i] < nArr[i+1] {
+            nArr.remove(at:i)
+            erase += 1
+            i = 0
+        } else{
+            i += 1
+        }
+    }
+    return nArr.joined(separator:"")
+}*/
+//654321 k=1 65432
+//654321 k=5 6
+//11111117 k=5
+
+/*다른 사람 풀이
+import Foundation
+
+func solution(_ number:String, _ k:Int) -> String {
+    let numbers = number.compactMap{ Int(String($0))}
+
+    var sub: [Int] = []
+
+    var k = k
+
+    for (i,e) in numbers.enumerated() {
+        while k>0, sub.isEmpty == false, sub.last! < e {
+            k-=1
+            sub.removeLast()
+        }
+
+        if k == 0 {
+            sub.append(contentsOf: numbers[i...])
+            break
+        } else {
+            sub.append(e)
+        }
+    }
+
+    return sub[..<(sub.count-k)].map {String($0)}.joined()
+}
+*/
\ No newline at end of file
diff --git "a/\355\225\234\352\267\274\354\230\201/\355\214\214\354\235\274\353\252\205\354\240\225\353\240\254_level2.swift" "b/\355\225\234\352\267\274\354\230\201/\355\214\214\354\235\274\353\252\205\354\240\225\353\240\254_level2.swift"
new file mode 100644
index 0000000..2ac0213
--- /dev/null
+++ "b/\355\225\234\352\267\274\354\230\201/\355\214\214\354\235\274\353\252\205\354\240\225\353\240\254_level2.swift"
@@ -0,0 +1,75 @@
+//220331
+//프로그래머스 [level2] 파일명 정렬 문제
+//https://programmers.co.kr/learn/courses/30/lessons/17686
+
+//파일명이 숫자로 끝날경우 number 부분 주의 필요
+func solution(_ files:[String]) -> [String] {
+    var arr: Array<fileStruct> = []
+
+    for f in files {
+        let lowerArray = f.map{$0.lowercased()}
+        let nums = lowerArray.filter{Character($0).isNumber == true}
+        let numberFirstIndex = lowerArray.firstIndex(of:nums[0])!
+        let head = Array(lowerArray[..<numberFirstIndex]).joined(separator:"")
+        //print(head)
+        let characters = Array(lowerArray[numberFirstIndex..<lowerArray.endIndex]).filter{Character($0).isNumber == false}
+        //print(characters)
+        var number: Int
+        if characters.count == 0 {
+            number = Int(Array(lowerArray[numberFirstIndex..<lowerArray.endIndex]).joined(separator:""))!
+        } else{
+            let numberLastIndex = Array(lowerArray[numberFirstIndex..<lowerArray.endIndex]).firstIndex(of:characters[0])!
+        //print(numberLastIndex)
+        number = Int(Array(lowerArray[numberFirstIndex..<numberFirstIndex+numberLastIndex]).joined(separator:""))!
+        }
+
+        let s = fileStruct(name:f,Head: head ,Number:number)
+        arr += [s]
+    }
+
+    let newArr = arr.sorted(by:{$0.Number < $1.Number})
+    let newArr2 = newArr.sorted(by: {$0.Head < $1.Head})
+
+    let answer = newArr2.map {$0.name}
+
+    return answer
+}
+
+struct fileStruct {
+    var name: String
+    var Head: String
+    var Number: Int
+}
+
+/*
+정렬 부분 참조
+https://gonslab.tistory.com/35
+*/
+
+
+/*
+다른 사람 풀이
+
+extension String{
+    var numeric: ClosedRange<Character> { return "0"..."9" }
+    var head: String{
+        return self.prefix { numeric.contains($0) == false }.uppercased()
+    }
+    var number: Int {
+        return Int( self.drop   { numeric.contains($0) == false}
+                        .prefix { numeric.contains($0) == true })!
+    }
+}
+
+func solution(_ files:[String]) -> [String] {
+
+    return files.enumerated().sorted { (lhs, rhs) in
+        let l = lhs.element
+        let r = rhs.element
+        if l.head != r.head { return l.head < r.head}
+        if l.number != r.number { return l.number < r.number}
+        return lhs.offset < rhs.offset
+
+    }.map{ $0.element }
+}
+*/
\ No newline at end of file
diff --git "a/\355\225\234\352\267\274\354\230\201/\355\224\204\353\240\214\354\246\2104\353\270\224\353\241\235_level2.swift" "b/\355\225\234\352\267\274\354\230\201/\355\224\204\353\240\214\354\246\2104\353\270\224\353\241\235_level2.swift"
new file mode 100644
index 0000000..c131d79
--- /dev/null
+++ "b/\355\225\234\352\267\274\354\230\201/\355\224\204\353\240\214\354\246\2104\353\270\224\353\241\235_level2.swift"
@@ -0,0 +1,54 @@
+//220328
+//프로그래머스 [level2] 프렌즈4블록 문제
+//https://programmers.co.kr/learn/courses/30/lessons/17679
+
+func solution(_ m:Int, _ n:Int, _ board:[String]) -> Int {
+    var pre_answer = 0
+    var answer = 0
+    var answerArr = [[Int]]()
+    var arr = Array(repeating:Array(repeating:"0",count:n),count:m)
+    for (i,b) in board.enumerated(){
+        arr[i] = b.map{String($0)}
+    }
+
+    repeat{
+        pre_answer = answer
+        //행,열 탐색해서 같은 거 있으면 answerArr에 좌표 넣기
+        for i in stride(from:0,to:m-1,by:1){ //행
+            for j in stride(from:0,to:n-1,by:1){ //열
+                if arr[i][j] == "0" {continue}
+                if arr[i][j] == arr[i+1][j] && arr[i][j] == arr[i][j+1] && arr[i][j] == arr[i+1][j+1]{
+                    answerArr = answerArr + [[i,j]]+[[i+1,j]]+[[i,j+1]]+[[i+1,j+1]]
+                }
+            }
+        }
+
+        //answerArr 중복 없애기
+        answerArr = Array(Set(answerArr))
+
+        //answerArr에 있는 좌표 모두 0 만들기
+        answer += answerArr.count
+        for i in answerArr{
+            arr[i[0]][i[1]] = "0"
+        }
+
+        //arr 배열 재배치
+        for j in stride(from:0,to:n,by:1){ //열
+            var first = 0 //블록이 내려와야할 행 위치
+            if arr[m-1][j] == "0" {first = m-1}
+            for i in stride(from:m-2,through:0,by:-1){ //행
+                if arr[i][j] == "0"{
+                    if i>first {first = i }
+                }
+                else if arr[i+1][j] == "0"{
+                    arr[first][j] = arr[i][j]
+                    arr[i][j] = "0"
+                    first -= 1
+                }
+            }
+        }
+        //answerArr 다시 빈 배열 만들기
+        answerArr = [[Int]]()
+    } while(pre_answer<answer)
+    return answer
+}
\ No newline at end of file