题目描述

数据范围

对于100%的数据，n<=100000，1<=A[i]<=5000

=w=

Ans=∏1ai

代码

#include
     
      #include
      
       #include
       
        #include
        
         #include
         
          #define ll long longusing namespace std;const char* fin="aP1.in";const char* fout="aP1.out";const ll inf=0x7fffffff;const ll maxn=100007,mo=998244353;ll n,i,j,k;ll a[maxn],fact[maxn];ll ans;ll qpower(ll a,ll b){    ll c=1;    while (b){        if (b&1) c=c*a%mo;        a=a*a%mo;        b>>=1;    }    return c;}ll N(ll v){    return qpower(v,mo-2);}ll read(){    ll x=0;    char ch=getchar();    while (ch<'0' || ch>'9') ch=getchar();    while (ch>='0' && ch<='9') x=x*10+ch-'0',ch=getchar();    return x;}int main(){    scanf("%lld",&n);    j=1;    for (i=1;i<=n;i++) j=(j*N(read()))%mo;    printf("%lld",j);    return 0;}
         
        
       
      
     

=o=

拿几个较小的数据推一推便发现规律。