Merge branch 'master' of github.com:DylanFrank/ACM_code

Author: taotao

Diff for: math/数论算法模板总结.md

@@ -280,3 +280,29 @@ LL MLE(int *r,int *mod,int n){
 }
 
 ```
+#莫比乌斯反演
+线性筛法$O(n)$
+```c++
+int prime[maxn],cnt;
+int mu[maxn];
+
+void init_mobius(){
+    memset(prime,0,sizeof(prime));
+    mu[1] =1;
+    cnt =0;
+    for(int i=2 ;i<maxn ; ++i){
+        if(!prime[i]){
+            prime[cnt++] = i;
+            mu[i] = -1;
+        }
+        for(int j=0 ; j<cnt && i*prime[j]<maxn ; ++j){
+            prime[i*prime[j]] = 1;
+            if(i%prime[j])mu[i*prime[j]] = -mu[i];
+            else {
+                mu[i*prime[j]] = 0;
+                break;
+            }
+        }
+    }
+}
+```