'commit'

TangDou/AcWing/RongChi/HDU2204_2.cpp

@@ -3,6 +3,7 @@ using namespace std;
 #define LL long long
 const int N = 100 + 100;
 
+// 筛法求莫比乌斯函数
 LL mu[N], sum[N];
 int primes[N], cnt;
 bool st[N];
@@ -24,19 +25,18 @@ void get_mobius(LL n) {
         }
     }
     // 维护u(x)前缀和
+    // 这玩意有啥用？
     for (LL i = 1; i <= n; i++) sum[i] = sum[i - 1] + mu[i];
 }
 
 int main() {
     get_mobius(N - 1);
 
-    LL tmp;
+    LL t;
-    while (cin >> tmp) {
+    while (cin >> t) {
-        LL sum = 1;
+        LL s = 1;
-        for (LL i = 2; i <= 64; i++) {
+        for (LL i = 2; i <= 64; i++) s -= mu[i] * (LL)(pow(t * 1.0, 1.0 / i) - 1);
-            sum -= mu[i] * (LL)(pow(tmp * 1.0, 1.0 / i) - 1);
+        cout << s << endl;
-        }
-        cout << sum << endl;
     }
     return 0;
 }