Merge pull request #1767 from AlgorithmWithGod/khj20006

[20260103] BOJ / P2 / 최대공약수 게임 / 권혁준

Author: ShinHeeEul

khj20006/202601/03 BOJ P2 최대공약수 게임.md

@@ -0,0 +1,41 @@
+```cpp
+#include <bits/stdc++.h>
+using namespace std;
+
+int N, X;
+vector<int> primes;
+bool ex[301][512]{};
+bitset<512> base;
+
+int main() {
+    cin.tie(0)->sync_with_stdio(0);
+
+    cin>>N>>X;
+    for(int i=2;i*i<=X;i++) if(X%i == 0) {
+        primes.push_back(i);
+        while(X%i == 0) X /= i;
+    }
+    if(X != 1) primes.push_back(X);
+
+    ex[0][(1<<primes.size())-1] = 1;
+    for(int i=1,a;i<=N;i++) {
+        cin>>a;
+        int mask = 0;
+        for(int j=0;j<primes.size();j++) if(a%primes[j] == 0) mask |= (1<<j);
+        
+        for(int j=i-1;j>=0;j--) for(int k=1;k<512;k++) if(ex[j][k] && (k&mask)) {
+            ex[j+1][k&mask] = 1;
+            if(k != mask) base[k] = 1;
+        }
+    }
+    
+    for(int k=1;k<512;k++) if(!base[k]) {
+        for(int j=N;j>=0;j--) if(ex[j][k]) {
+            if(j&1) return cout<<"First",0;
+            break;
+        }
+    }
+    cout<<"Second";
+
+}
+```