LIGHT OJ 1370 欧拉函数（在小于自身的正整数中有n个与自身互素的数，这样的数最小的为n后第一个素数）

Posted 2020-08-12 十目

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cstring>
 4 #include<string>
 5 #include<algorithm>
 6 #include <cmath>
 7 using namespace std;
 8 typedef long long ll;
 9 const ll INF = -100000000000ll;
10 const double eps = 1e-8;
11 const int maxn = 1e6 + 10;
12 const double PI = acos(-1);
13 int pre[maxn];
14 void init(){
15     pre[1] = 1;
16     for(int i = 2;i <= 1000005;i++)
17         if(!pre[i]){
18             for(int j = i*2;j <= 1000005;j += i)
19                 pre[j] = 1;
20         }
21 
22 }
23 int main()
24 {
25   //  freopen("in.txt","r",stdin);
26     init();
27     int T,cas = 0;
28     cin>>T;
29     while(T--){
30         int n,a;
31         cas++;
32         scanf("%d",&n);
33         ll ans = 0;
34         for(int i = 1;i <= n;i++){
35             scanf("%d",&a);
36             a++;
37             while(pre[a]) a++;
38            // cout<<i<<" "<<a<<endl;
39             ans += a;
40         }
41 
42         printf("Case %d: %lld Xukha\n",cas,ans);
43     }
44 
45     return 0;
46 }