3884. 上帝与集合的正确用法

https://darkbzoj.cc/submission/191438

BZOJ/3884/3884.cpp

@@ -0,0 +1,43 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+long long phi(long long x) {
+    long long r = x;
+    for (long long i = 2; i * i <= x; i++)
+        if (x % i == 0) {
+            r = r / i * (i - 1);
+            while (x % i == 0) {
+                x /= i;
+            }
+        }
+    if (x > 1) {
+        r = r / x * (x - 1);
+    }
+    return r;
+}
+
+long long pow(long long x, long long y, long long mod) {
+    long long r = 1;
+    while (y) {
+        if (y & 1) r = (r * x) % mod;
+        x = (x * x) % mod, y >>= 1;
+    }
+    return r;
+}
+
+long long f(long long x) {
+    if (x == 1) return 0;
+    long long n = phi(x);
+    return pow(2, n + f(n), x);
+}
+
+int main() {
+    long long t, x;
+    cin >> t;
+    while (t--) {
+        cin >> x;
+        cout << f(x) << endl;
+    }
+    return 0;
+}