diff --git "a/src/dayoung/week17/\353\213\244\353\213\250\352\263\204\354\271\253\354\206\224\355\214\220\353\247\244.swift" "b/src/dayoung/week17/\353\213\244\353\213\250\352\263\204\354\271\253\354\206\224\355\214\220\353\247\244.swift"
new file mode 100644
index 0000000..ff67f06
--- /dev/null
+++ "b/src/dayoung/week17/\353\213\244\353\213\250\352\263\204\354\271\253\354\206\224\355\214\220\353\247\244.swift"
@@ -0,0 +1,44 @@
+//
+//  main.swift
+//  week17
+//
+//  Created by 장다영 on 2021/07/18.
+//
+
+import Foundation
+
+func solution(_ enroll:[String], _ referral:[String], _ seller:[String], _ amount:[Int]) -> [Int] {
+    
+    var net = Dictionary<String, String>()
+    var profits = Dictionary<String ,Int>()
+    
+    profits["-"] = 0
+    
+    func money(_ profit: Int) -> Int {
+        return Int(Double(profit) * 0.1)
+    }
+    
+    func pass(_ name: String, earn: Int) {
+        if earn == 0 {
+            return
+        }
+        
+        profits[name]! += earn
+        if name != "-" {
+            profits[name]! -= money(earn)
+            pass(net[name]!, earn: money(earn))
+        }
+    }
+    
+    for i in 0..<enroll.count {
+        net[enroll[i]] = referral[i]
+        profits[enroll[i]] = 0
+    }
+    
+    for i in 0..<seller.count {
+        pass(net[seller[i]]!, earn: money(amount[i] * 100))
+        profits[seller[i]]! += amount[i] * 90
+    }
+    
+    return enroll.map{profits[$0]!}
+}
diff --git "a/src/dayoung/week17/\354\230\244\355\224\210\354\261\204\355\214\205\353\260\251.swift" "b/src/dayoung/week17/\354\230\244\355\224\210\354\261\204\355\214\205\353\260\251.swift"
new file mode 100644
index 0000000..64ce880
--- /dev/null
+++ "b/src/dayoung/week17/\354\230\244\355\224\210\354\261\204\355\214\205\353\260\251.swift"
@@ -0,0 +1,34 @@
+//
+//  오픈채팅방.swift
+//  week17
+//
+//  Created by 장다영 on 2021/07/18.
+//
+
+import Foundation
+
+func solution(_ record:[String]) -> [String] {
+    var nickName: [String : String] = [:]
+    var result: [String] = []
+    
+    for i in record {
+        let arr = i.components(separatedBy: " ")
+        
+        if arr.count > 2 {
+            nickName[arr[1]] = arr[2]
+        }
+    }
+    
+    for i in record {
+        let arr = i.components(separatedBy: " ")
+        let name = nickName[arr[1]]!
+        
+        if arr[0] == "Enter" {
+            result.append("\(name)님이 들어왔습니다.")
+        }
+        else if arr[0] == "Leave" {
+            result.append("\(name)님이 나갔습니다.")
+        }
+    }
+    return result
+}
diff --git a/src/sangmin/week17/BOJ5557/.vscode/settings.json b/src/sangmin/week17/BOJ5557/.vscode/settings.json
new file mode 100644
index 0000000..d7d9270
--- /dev/null
+++ b/src/sangmin/week17/BOJ5557/.vscode/settings.json
@@ -0,0 +1,65 @@
+{
+    "files.associations": {
+        "__bit_reference": "cpp",
+        "__config": "cpp",
+        "__debug": "cpp",
+        "__errc": "cpp",
+        "__functional_base": "cpp",
+        "__hash_table": "cpp",
+        "__locale": "cpp",
+        "__mutex_base": "cpp",
+        "__node_handle": "cpp",
+        "__nullptr": "cpp",
+        "__split_buffer": "cpp",
+        "__string": "cpp",
+        "__threading_support": "cpp",
+        "__tuple": "cpp",
+        "algorithm": "cpp",
+        "array": "cpp",
+        "atomic": "cpp",
+        "bit": "cpp",
+        "bitset": "cpp",
+        "cctype": "cpp",
+        "chrono": "cpp",
+        "clocale": "cpp",
+        "cmath": "cpp",
+        "complex": "cpp",
+        "cstdarg": "cpp",
+        "cstddef": "cpp",
+        "cstdint": "cpp",
+        "cstdio": "cpp",
+        "cstdlib": "cpp",
+        "cstring": "cpp",
+        "ctime": "cpp",
+        "cwchar": "cpp",
+        "cwctype": "cpp",
+        "exception": "cpp",
+        "functional": "cpp",
+        "initializer_list": "cpp",
+        "ios": "cpp",
+        "iosfwd": "cpp",
+        "iostream": "cpp",
+        "istream": "cpp",
+        "iterator": "cpp",
+        "limits": "cpp",
+        "locale": "cpp",
+        "memory": "cpp",
+        "mutex": "cpp",
+        "new": "cpp",
+        "optional": "cpp",
+        "ostream": "cpp",
+        "ratio": "cpp",
+        "sstream": "cpp",
+        "stdexcept": "cpp",
+        "streambuf": "cpp",
+        "string": "cpp",
+        "string_view": "cpp",
+        "system_error": "cpp",
+        "tuple": "cpp",
+        "type_traits": "cpp",
+        "typeinfo": "cpp",
+        "unordered_map": "cpp",
+        "utility": "cpp",
+        "vector": "cpp"
+    }
+}
\ No newline at end of file
diff --git a/src/sangmin/week17/BOJ5557/main b/src/sangmin/week17/BOJ5557/main
new file mode 100755
index 0000000..081827f
Binary files /dev/null and b/src/sangmin/week17/BOJ5557/main differ
diff --git a/src/sangmin/week17/BOJ5557/main.cpp b/src/sangmin/week17/BOJ5557/main.cpp
new file mode 100644
index 0000000..afa6189
--- /dev/null
+++ b/src/sangmin/week17/BOJ5557/main.cpp
@@ -0,0 +1,29 @@
+#include <iostream>
+#define MAX 110
+using namespace std;
+
+int N;
+int ary[MAX];
+long long dp[MAX][30];
+
+int main(){
+    cin >> N;
+    for(int i = 1; i<=N; i++)
+        cin >> ary[i];
+    ary[0] = 0;
+    dp[0][0] = 0;
+
+    dp[1][ary[1]] = 1;
+    for(int i = 2; i<=N; i++){
+        for(int j = 0; j<=20; j++){
+            if(dp[i-1][j] >= 0){
+                if(j - ary[i] >= 0) dp[i][j-ary[i]] += dp[i-1][j];
+                if(j + ary[i] <= 20) dp[i][j+ary[i]] += dp[i-1][j];
+            }
+        }
+    }
+
+    cout << dp[N-1][ary[N]] << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/src/sangmin/week17/BOJ5557/main.dSYM/Contents/Info.plist b/src/sangmin/week17/BOJ5557/main.dSYM/Contents/Info.plist
new file mode 100644
index 0000000..fe7fecd
--- /dev/null
+++ b/src/sangmin/week17/BOJ5557/main.dSYM/Contents/Info.plist
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+	<dict>
+		<key>CFBundleDevelopmentRegion</key>
+		<string>English</string>
+		<key>CFBundleIdentifier</key>
+		<string>com.apple.xcode.dsym.main</string>
+		<key>CFBundleInfoDictionaryVersion</key>
+		<string>6.0</string>
+		<key>CFBundlePackageType</key>
+		<string>dSYM</string>
+		<key>CFBundleSignature</key>
+		<string>????</string>
+		<key>CFBundleShortVersionString</key>
+		<string>1.0</string>
+		<key>CFBundleVersion</key>
+		<string>1</string>
+	</dict>
+</plist>
diff --git a/src/sangmin/week17/BOJ5557/main.dSYM/Contents/Resources/DWARF/main b/src/sangmin/week17/BOJ5557/main.dSYM/Contents/Resources/DWARF/main
new file mode 100644
index 0000000..dc6cb80
Binary files /dev/null and b/src/sangmin/week17/BOJ5557/main.dSYM/Contents/Resources/DWARF/main differ