Bzoj-22190儀仗隊オラ関数
13257 ワード
テーマリンク：http://www.lydsy.com/JudgeOnline/problem.php?id=2190
簡単なリラ関数の問題は、gcd(x，y)=1,0<=x，y<=nの対数です。
簡単なリラ関数の問題は、gcd(x，y)=1,0<=x，y<=nの対数です。
1 //STATUS:C++_AC_24MS_1584KB
2 #include <functional>
3 #include <algorithm>
4 #include <iostream>
5 //#include <ext/rope>
6 #include <fstream>
7 #include <sstream>
8 #include <iomanip>
9 #include <numeric>
10 #include <cstring>
11 #include <cassert>
12 #include <cstdio>
13 #include <string>
14 #include <vector>
15 #include <bitset>
16 #include <queue>
17 #include <stack>
18 #include <cmath>
19 #include <ctime>
20 #include <list>
21 #include <set>
22 #include <map>
23 using namespace std;
24 //#pragma comment(linker,"/STACK:102400000,102400000")
25 //using namespace __gnu_cxx;
26 //define
27 #define pii pair<int,int>
28 #define mem(a,b) memset(a,b,sizeof(a))
29 #define lson l,mid,rt<<1
30 #define rson mid+1,r,rt<<1|1
31 #define PI acos(-1.0)
32 //typedef
33 typedef long long LL;
34 typedef unsigned long long ULL;
35 //const
36 const int N=40010;
37 const int INF=0x3f3f3f3f;
38 const int MOD=100000,STA=8000010;
39 const LL LNF=1LL<<60;
40 const double EPS=1e-8;
41 const double OO=1e15;
42 const int dx[4]={-1,0,1,0};
43 const int dy[4]={0,1,0,-1};
44 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
45 //Daily Use ...
46 inline int sign(double x){return (x>EPS)-(x<-EPS);}
47 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
48 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
49 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
50 template<class T> inline T Min(T a,T b){return a<b?a:b;}
51 template<class T> inline T Max(T a,T b){return a>b?a:b;}
52 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
53 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
54 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
55 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
56 //End
57
58 int phi[N],prime[N];
59 int cnt;
60
61 void phitable(int n)
62 {
63 int i,j;
64 cnt=0;phi[1]=1;
65 for(i=2;i<=n;i++){
66 if(!phi[i]){
67 prime[cnt++]=i;
68 phi[i]=i-1;
69 }
70 for(j=0;j<cnt && i*prime[j]<=n;j++){
71 if(i%prime[j]){
72 phi[i*prime[j]]=phi[i]*(prime[j]-1);
73 }else {phi[i*prime[j]]=phi[i]*prime[j];break;}
74 }
75 }
76 }
77
78 int n;
79
80 int main(){
81 // freopen("in.txt","r",stdin);
82 int i,j,ans=0;
83 scanf("%d",&n);
84 phitable(n);
85 for(i=1;i<n;i++)ans+=phi[i];
86 printf("%d
",ans<<1|1);
87
88 return 0;
89 }