Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
#include <iostream> #include <cstdio> #include <cstdlib> #include <cmath> #include <algorithm> #include <climits> #include <cstring> #include <string> #include <set> #include <bitset> #include <map> #include <queue> #include <stack> #include <vector> #define rep(i,m,n) for(i=m;i<=n;i++) #define mod 1000000007 #define inf 0x3f3f3f3f #define vi vector<int> #define pb push_back #define mp make_pair #define fi first #define se second #define ll long long #define pi acos(-1.0) #define pii pair<int,int> #define sys system("pause") const int maxn=1e5+10; using namespace std; inline ll gcd(ll p,ll q){return q==0?p:gcd(q,p%q);} inline ll qpow(ll p,ll q){ll f=1;while(q){if(q&1)f=f*p;p=p*p;q>>=1;}return f;} inline void umax(ll &p,ll q){if(p<q)p=q;} inline void umin(ll &p,ll q){if(p>q)p=q;} inline ll read() { ll x=0;int f=1;char ch=getchar(); while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();} while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();} return x*f; } int n,m,k,t; bool vis[maxn]; vi fac[maxn]; void init() { for(int i=2;i<=maxn-10;i++) { if(vis[i])continue; for(int j=i;j<=maxn-10;j+=i) { vis[j]=true; fac[j].pb(i); } } } int gao(int x,int y) { int ret=0,num=fac[x].size(); for(int i=1;i<(1<<num);i++) { int now=1,cnt=0; for(int j=0;j<num;j++) { if(i&(1<<j)) { cnt++; now*=fac[x][j]; } } if(cnt&1)ret+=y/now; else ret-=y/now; } return y-ret; } int main() { int i,j; init(); scanf("%d",&t); while(t--) { scanf("%d%d",&m,&n); ll ret=0; rep(i,1,m) { ret+=gao(i,n); } printf("%lld\n",ret); } return 0; }
原文:http://www.cnblogs.com/dyzll/p/6360078.html