代码

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<time.h>
#include<unordered_map>
#include<set>
#include<bitset>
#include<string.h>
#include<queue>
#include<algorithm>
#define ci const int
#define iv inline void
#define ic inline ci
#define ull unsigned long long
//#define int unsigned
#define int long long
#define getchar getchar_unlocked
//#define int __int128
//#define NN 400
//#define N 405
#define N 5000000
#define M 105
#define mod 10007ll
#define inf 0x3f3f3f3f
//#define inf 0x3f3f3f3f3f3f3f3fll
ic re();const char getch();void pr(ci x);
void prs(ci x);void prn(ci x);
iv swp(int&a,int&b){a^=b^=a^=b;}
ic Abs(ci a){return a>0?a:-a;}
//big front small last
iv bfsl(int&a,int&b){a>b?void():swp(a,b);}
ic Max(ci A,ci B){return A>B?A:B;}
iv gma(int&A,ci B){A=Max(A,B);}
ic Min(ci A,ci B){return A<B?A:B;}
iv gmi(int&A,ci B){A=Min(A,B);}
ic gcd(ci a,ci b){return b?gcd(b,a%b):a;}
ic fpow(int a,int b=mod-2,ci md=mod){
	int c=1;
	while(b){
		if(b&1)c=c*a%md;
		a=a*a%md,b>>=1;
	}return c;
}
iv init(){;}
int a[5000010];
iv work(){
	for(int i=1;i<=N;++i){
		a[i]+=i<<1|1;
		for(int j=i<<1;j<=N;j+=i)
			a[j]-=a[i];
	}
	for(int i=1;i<N;++i)
		a[i+1]+=a[i];
	prn(a[N]);
}
/*
*/
signed main(){//srand(time(0));
	//freopen("in.txt","r",stdin);
	//freopen("gout.txt","w",stdout);
	//init();
	for(int T=1||re();T--;)work();
	//__builtin_parity(n);
	//__builtin_popcount(n);
}
void pri(ci x){if(x>9)pri(x/10);putchar(x%10^48);}
iv pr(ci x){if(x<0)putchar('-'),pri(-x);else pri(x);}
iv prs(ci x){pr(x);putchar(32);}
iv prn(ci x){pr(x);putchar(10);}
const char getch(){
	char c=getchar();
	while(!(c>47&&c<58||c>96&&c<123||c>64&&c<91))c=getchar();
	return c;
}
ic re(){
	int x=0;char c=getchar(),f=0;
	while(c<48||c>57)f|=(c=='-'),c=getchar();
	while(c>47&&c<58)x=x*10+(c^48),c=getchar();
	return f?-x:x;
}
/*
*/

评测结果