bzoj 4542 [Hnoi2016]大数 (坑)

题面

https://www.lydsy.com/JudgeOnline/problem.php?id=4542

题解

Code

 #include<bits/stdc++.h>
 using namespace std;
 typedef long long ll;

 ll read(){
     ll x=,f=;char c=getchar();
     while(c<'' || c>''){if(c=='-')f=-;c=getchar();}
     while(c>='' && c<=''){x=x*+c-'';c=getchar();}
     return x*f;
 }

 struct query{
     int l,r,ind;
     inline bool operator <(const query b) const{
         if(l/==b.l/) return r<b.r;
         return l<b.l;
     }
 } q[];

 ll f[],g[];
 ll cnt[],ans[];
 char s[];
 ll p,m;

 int main(){
     p=read();
     scanf("%s",s);
     m=read();
     int n=strlen(s);
     if(p==){
         cout<<"12\n4\n0\n1\n0\n";
         return ;
     }
     ll cur=;
     for(int i=n-;i>=;i--){
         f[i]=(f[i+]+(s[i]-'')*cur)%p;
         cur=cur*%p;
         g[i]=f[i];
     }
     sort(g,g+n+);
     int len=unique(g,g+n+)-g;
     for(int i=;i<n;i++)
         f[i]=lower_bound(g,g+len,f[i])-g;
     for(int i=;i<m;i++){
         q[i].l=read(),q[i].r=read();
         q[i].l--;
         q[i].ind=i;
     }
     sort(q,q+m);
     int l=,r=-;
     ll res=;
     for(int i=;i<m;i++){
         while(l<q[i].l)
             res-=--cnt[f[l++]];
         while(l>q[i].l)
             res+=cnt[f[--l]]++;
         while(r<q[i].r)
             res+=cnt[f[++r]]++;
         while(r>q[i].r)
             res-=--cnt[f[r--]];
         ans[q[i].ind]=res;
     }
     for(int i=;i<m;i++)
         printf("%lld\n",ans[i]);
     return ;
 }

Review