2301: [HAOI2011]Problem b
Time Limit: 50 Sec Memory Limit: 256 MB
Submit: 7931 Solved: 3876
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Description
For the given n queries, how many pairs of numbers (x,y) can be found each time, a ≤ x ≤ b, c ≤ y ≤ d, and gcd(x,y) = k, gcd(x,y) function is the greatest common divisor of X and y.
Input
The first line is a n integer n, a n d the next N lines are five integers representing a, b, c, D and k respectively
Output
There are n lines in total. An integer in each line indicates the number of pairs (x,y) that meet the requirements
Sample Input
2
2 5 1 5 1
1 5 1 5 2
Sample Output
14
3
HINT
100% of the data meet the following requirements: 1 ≤ n ≤ 50000, 1 ≤ a ≤ b ≤ 50000, 1 ≤ c ≤ d ≤ 50000, 1 ≤ k ≤ 50000
Thought: but it's the basic problem of Mobius inversion. See blog for details https://blog.csdn.net/huayunhualuo/article/details/51378405
Code:
#include<iostream> #include<cmath> #include<iomanip> #include<cstring> #include<algorithm> #include<cstdio> #include<string> #include<queue> #include<vector> #include<map> #define ll long long #define inf 0x3f3f3f3f3f3f3f3fLL using namespace std; const int maxn=1e5+10; ll mu[maxn],pri[maxn]; ll a,b,c,d,k; ll sum[maxn]; bool ok[maxn]; void init() { mu[1]=sum[1]=1; ll cnt=0; for(ll i=2;i<maxn;i++) { if(!ok[i]) { pri[cnt++]=i; mu[i]=-1; } for(ll j=0;j<cnt&&i*pri[j]<maxn;j++) { ok[i*pri[j]]=1; if(i%pri[j]) mu[i*pri[j]]=-mu[i]; else { mu[i*pri[j]]=0; break; } } sum[i]=sum[i-1]+mu[i]; } } ll jud(ll x,ll y) { x/=k;y/=k; if(x>y) swap(x,y); ll ans=0; for(ll i=1,l=1;i<=x;i=l+1) { l=min(x/(x/i),y/(y/i)); ans+=(sum[l]-sum[i-1])*(x/i)*(y/i); } return ans; } int main() { int T,cas=1; init(); scanf("%d",&T); while(T--) { scanf("%lld%lld%lld%lld%lld",&a,&b,&c,&d,&k); //printf("Case %d: ",cas++); if(!k) { printf("0\n"); continue; } else { ll ans=jud(b,d)+jud(a-1,c-1)-jud(a-1,d)-jud(b,c-1); printf("%lld\n",ans); } } return 0; }