智乃酱的区间乘积

题目链接:智乃酱的区间乘积

题意：离线求区间乘积，直接处理前缀乘积就可以啦，不过要注意逆元

参考代码

#include<bits/stdc++.h>
using namespace std;
#define int long long 
#define INF 0x3f3f3f3f3f3f3f3f
#define  x first
#define y second
typedef pair<int,int>PII;
int max(int a,int b)
{
    if(a>=b) return a;
    else return b;
}
int min(int a,int b)
{
    if(a>=b) return b;
    else return a;
}
inline int read()
{
    int X=0; bool flag=1; char ch=getchar();
    while(ch<'0'||ch>'9') {if(ch=='-') flag=0; ch=getchar();}
    while(ch>='0'&&ch<='9') {X=(X<<1)+(X<<3)+ch-'0'; ch=getchar();}
    if(flag) return X;
    return ~(X-1);
}
int qmi(int a,int b,int c)    
{
    int res=1%c;
    while(b)
    {
        if(b&1) res=res*a%c;
        a=a*a%c;
        b>>=1;
    }
    return res;
}
int gcd(int a,int b)   
{
    return b?gcd(b,a%b):a;
}
const int mod=1e9+7;
const int N=1e5+10;
int s[N]; 
void solve()
{
    s[0]=1;
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        int k;
        cin>>k;
        s[i]=s[i-1]*k%mod;
        //cout<<s[i]<<endl;
    }
    while(m--)
    {
        int l,r;
        cin>>l>>r;
        int ans=s[r]*qmi(s[l-1],mod-2,mod)%mod;
        cout<<ans<<endl;
    }
}
signed main()
{
         ios_base::sync_with_stdio(false);
         cin.tie(0);
         int t;
         t=1;
         while(t--) 
        {
            solve();
        }
       return 0;

}