D - Jzzhu and Numbers

https://codeforces.com/contest/449/submission/184326882

Codeforces/449/449.cpp

@@ -0,0 +1,52 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int mod = 1e9 + 7;
+
+int n, s[1 << 20], ans;
+
+int binpow(int a, int b) {
+    int res = 1;
+
+    while (b) {
+        if (b & 1) res = static_cast<long long>(res) * a % mod;
+        a = static_cast<long long>(a) * a % mod;
+        b >>= 1;
+    }
+
+    return res;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1, x; i <= n; i++) {
+        cin >> x;
+
+        s[(1 << 20) - 1 - x]++;
+    }
+
+    for (int i = 0; i < 20; i++) {
+        for (int j = 0; j < 1 << 20; j++) {
+            if (j & (1 << i)) {
+                s[j] += s[j ^ (1 << i)];
+            }
+        }
+    }
+
+    ans = binpow(2, n);
+
+    for (int i = 0; i < (1 << 20) - 1; i++) {
+        ans = (static_cast<long long>(ans) + (__builtin_popcount(i) % 2 ? -1 : 1) * binpow(2, s[i])) % mod;
+    }
+
+    cout << (ans + mod) % mod << endl;
+
+    return 0;
+}