diff --git "a/leetcode3/\353\263\200\354\247\200\355\230\221/v2/3803. Count Residue Prefixes.py" "b/leetcode3/\353\263\200\354\247\200\355\230\221/v2/3803. Count Residue Prefixes.py"
new file mode 100644
index 00000000..483a4d83
--- /dev/null
+++ "b/leetcode3/\353\263\200\354\247\200\355\230\221/v2/3803. Count Residue Prefixes.py"	
@@ -0,0 +1,23 @@
+'''
+1. 아이디어 :
+set에 기록하고 길이 재서 구한다.
+
+2. 시간복잡도 :
+    O(n)
+
+3. 자료구조/알고리즘 :
+'''
+class Solution:
+    def residuePrefixes(self, s: str) -> int:
+        n = len(s)
+        ans = 0
+        st = set()
+
+        for i in range(n):
+            st.add(s[i])
+            # print(st, (i+1) % 3)
+            if len(st) == (i + 1) % 3:
+                ans += 1
+            
+
+        return ans
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diff --git "a/leetcode3/\353\263\200\354\247\200\355\230\221/v2/837. New 21 Game.py" "b/leetcode3/\353\263\200\354\247\200\355\230\221/v2/837. New 21 Game.py"
new file mode 100644
index 00000000..3c416139
--- /dev/null
+++ "b/leetcode3/\353\263\200\354\247\200\355\230\221/v2/837. New 21 Game.py"	
@@ -0,0 +1,30 @@
+'''
+1. 아이디어 :
+randint로 그냥 다 구하려고 했으나 시간초과 발생
+
+2. 시간복잡도 :
+
+3. 자료구조/알고리즘 :
+'''
+from random import randint
+
+class Solution:
+    def playGame(self, k, maxPts):
+        _sum = 0
+        while True:
+            _sum += randint(1,maxPts)
+            if _sum >= k:
+                return _sum
+
+    def new21Game(self, n: int, k: int, maxPts: int) -> float:
+        plays = []
+        length = 500000
+
+        for i in range(length):
+            plays.append(self.playGame(k,maxPts))
+
+        # print(plays)
+        
+        plays = [i for i in plays if i <= n]
+        return len(plays) / length
+        
\ No newline at end of file