From 7df3cbab14de7bd9b3eac3884433e31f2cf77866 Mon Sep 17 00:00:00 2001
From: oncsr <khj20006@naver.com>
Date: Sat, 8 Mar 2025 18:28:09 +0900
Subject: [PATCH] =?UTF-8?q?[20250308]=20BOJ=20/=20G2=20/=20MEX=20/=20?=
 =?UTF-8?q?=EA=B6=8C=ED=98=81=EC=A4=80?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 khj20006/202503/08 BOJ G2 MEX.md | 82 ++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 khj20006/202503/08 BOJ G2 MEX.md

diff --git a/khj20006/202503/08 BOJ G2 MEX.md b/khj20006/202503/08 BOJ G2 MEX.md
new file mode 100644
index 00000000..ddbe5d96
--- /dev/null
+++ b/khj20006/202503/08 BOJ G2 MEX.md	
@@ -0,0 +1,82 @@
+## JAVA
+```java
+
+import java.util.*;
+import java.io.*;
+
+
+class Main {
+	
+	// IO field
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	static StringTokenizer st;
+
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static int nextInt() {return Integer.parseInt(st.nextToken());}
+	static long nextLong() {return Long.parseLong(st.nextToken());}
+	static void bwEnd() throws Exception {bw.flush();bw.close();}
+	
+	// Additional field
+
+	static int N;
+    static boolean[] A = new boolean[2200001];
+    static boolean[] B = new boolean[2200001];
+    
+	public static void main(String[] args) throws Exception {
+			
+		ready();
+		solve();
+	
+		bwEnd();
+		
+	}
+	
+	static void ready() throws Exception{
+		
+		N = Integer.parseInt(br.readLine());
+        for(nextLine();N-->0;A[nextInt()]=true);
+		
+	}
+	
+	static void solve() throws Exception{
+		
+		for(int i=0;i<=2200000;i++) {
+            if(!A[i] && !B[i]){
+                bw.write(i + "\n");
+                return;
+            }
+            if(i<2 || !A[i]) continue;
+            for(long j=i*2;j<=Math.min(2200000L,(long)i*i);j+=i) B[(int)j] = true;
+        }
+		
+	}
+	
+}
+
+```
+
+## C++
+```cpp
+
+#include <iostream>
+#include <bitset>
+using namespace std;
+using ll = long long;
+
+int main() {
+    cin.tie(0)->sync_with_stdio(0);
+
+    int N;
+    cin>>N;
+    bitset<2200001> A, B;
+    for(int a;N--;A[a]=1) cin>>a;
+    for(int i=0;i<2200001;i++) {
+        if(!A[i] && !B[i]) return cout<<i,0;
+        if(i < 2 || !A[i]) continue;
+        for(ll j=i*2;j<=min(2200000LL, (ll)i*i);j+=i) B[j] = 1;
+    }
+
+}
+
+```