1213 解的个数[一中数论随堂练]

#include<iostream>
#include<algorithm>
#include<math.h>
using namespace std;
typedef long long ll;
double z[10];
void exgcd(ll a,ll b,ll &d,ll &x,ll &y){
    if(!b){d=a;x=1;y=0;return;}
    exgcd(b,a%b,d,y,x);y-=x*(a/b);
}
int main(){
    ll a,b,c,p,q,r,s,x,y,d,k;
    int n;cin>>n;
    while(n--){
        cin>>a>>b>>c>>p>>q>>r>>s;c=-c;
        if(p>q||r>s||(!a&&!b&&c)){cout<<0<<endl;continue;}
        if(!a||!b){
            if(!a) a=q-p+1;
            else if(c%a==0&&(c/a)<=q&&(c/a)>=p) a=1;
            else a=0;
            if(!b) b=s-r+1;
            else if(c%b==0&&(c/b)<=s&&(c/b)>=r) b=1;
            else b=0;
            cout<<a*b<<endl;
            continue;
        }
        exgcd(a,b,d,x,y);
        if(c%d!=0){cout<<0<<endl;continue;}
        k=c/d;x*=k;y*=k;
        a=a/d;b=b/d;
        z[0]=(q-x)*1.0/b;
        z[1]=(p-x)*1.0/b;
        z[2]=(y-s)*1.0/a;
        z[3]=(y-r)*1.0/a;
        sort(z,z+4);
        a=floor(z[2]);b=ceil(z[1]);
        cout<<a-b+1<<endl;
    }
    return 0;
}

#include<cstdio>
#include<iostream>
#define ll long long
using namespace std;
ll n,a,b,c,p,q,r,l,ans;
int main(){
    cin>>n; 
    for(int i=1;i<=n;i++){
        cin>>a>>b>>c>>p>>q>>l>>r;
        ans=0;
        if(b==0){
            for(int x=p;x<=q;x++){
                if(x*a==-c) ans++;
            }
            cout<<ans*(r-l+1)<<endl;
        }
        else{
            for(int x=p;x<=q;x++){
                if((-c-a*x)%b==0&&(-c-a*x)*1.0/b>=l&&(-c-a*x)*1.0/b<=r) ans++;
            }
            cout<<ans<<endl;
        }
    }
    return 0;
}