'commit'

TangDou/AcWing/RongChi/HDU2204_2.cpp

@@ -3,18 +3,9 @@ using namespace std;
 #define int long long
 #define endl "\n"
 const int N = 110;
-/*
-10
-36
-1000000000000000000
 
-4
-9
-1001003332
-*/
 // 筛法求莫比乌斯函数
-int mu[N], sum[N];
-int primes[N], cnt;
+int mu[N], primes[N], cnt;
 bool st[N];
 void get_mobius(int n) {
     mu[1] = 1;
@@ -30,12 +21,9 @@ void get_mobius(int n) {
                 mu[t] = 0;
                 break;
             }
-            mu[t] = mu[i] * -1;
+            mu[t] = -mu[i];
         }
     }
-    // 维护u(x)前缀和
-    // 这玩意有啥用？
-    for (int i = 1; i <= n; i++) sum[i] = sum[i - 1] + mu[i];
 }
 
 signed main() {