A - mod M

https://atcoder.jp/contests/arc148/submissions/35176980

AtCoder/ARC148/A/A.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+#include <algorithm>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+
+int n, a[N], ans;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    std::sort(a + 1, a + 1 + n);
+
+    for (int i = 2; i <= n; i++) {
+        ans = std::__gcd(ans, a[i] - a[i - 1]);
+    }
+
+    cout << (ans == 1 ? 2 : 1) << endl;
+
+    return 0;
+}