3990 中国余数定理 2[一中数论随堂练]

#include<iostream>
#define maxn 11
using namespace std;
#define ll long long
ll yushu[maxn],mod[maxn];
void excgcd(ll a,ll b,ll &x,ll &y){
    if(b==0){
        x=1;
        y=0;
        return;
    }
    ll x1,y1;
    excgcd(b,a%b,x1,y1);
    x=y1;
    y=x1-(a/b)*y1;
    return;
}
int main(){
    ll s=1,l,r;
    int n;
    cin>>n>>l>>r;
    for(int i=0;i<n;i++){
        ll mo,yu;
        cin>>mo>>yu;
        yu=yu%mo;
        s*=mo;
        yushu[i]=yu;
        mod[i]=mo;
    }
    ll ans=0;
    for(int i=0;i<n;i++){
        ll mi=s/mod[i];
        ll x,y;
        excgcd(mi,mod[i],x,y);
        ans+=yushu[i]*mi*x;
    }
    while(ans>l){
        ans-=s;
    }
    ll sum=0,minn=0;
    for(int i=1;;i++){
        ans+=s;
        if(ans<=r){
            if(ans>=l){
                if(sum==0){
                    minn=ans;
                }
                sum++;
            }
        }
        else break;
    }
    cout<<sum<<endl<<minn;
    return 0;
}