bzoj 4542: [Hnoi2016]大数

#include<cstdio>

#include<cstdlib>

#include<cstring>

#include<algorithm>

#include<map>

#include<cmath>

#define ll long long

#define inf 1e9

#define eps 1e-8

#define N 100010

using namespace std;

struct QQ { int l,r,id;} q[N];

map<ll,int> mp;

ll s[N],ans[N];

int pos[N],c[N];

char st[N];

ll md,sum=0;

int n,m;

void ycl()

{

if (md!=2&&md!=5)

{

ll mi=1;

for (int i=n;i;i--)

{

s[i]=(s[i+1]+mi*(st[i]-'0'))%md;

mi=mi*10%md;

}

int cnt=0;

for (int i=1;i<=n+1;i++)

{

if (mp[s[i]]==0) mp[s[i]]=++cnt;

s[i]=mp[s[i]];

}

}

else for (int i=1;i<=n;i++) s[i]=((st[i]-'0')%md==0);

int k=sqrt(n);

for (int i=1;i<=n;i++) pos[i]=(i-1)/k+1;

}

bool cmp (QQ a,QQ b) { return pos[a.l]==pos[b.l]?a.r<b.r:a.l<b.l;}

void solve_25()

{

int l=1,r=0,ps=0; sum=0;

for (int i=1;i<=m;i++)

{

while (q[i].l<l) { l--; ps+=s[l]; sum+=ps; }

while (r<q[i].r) { r++; if (s[r]) sum+=r-l+1,ps++; }

while (l<q[i].l) { sum-=ps; ps-=s[l]; l++; }

while (q[i].r<r) { if (s[r]) sum-=r-l+1,ps--; r--; }

ans[q[i].id]=sum;

}

}

void add(int x)

{

sum+=c[s[x]]; c[s[x]]++;

}

void del(int x)

{

c[s[x]]--; sum-=c[s[x]];

}

void solve_p()

{

int l=1,r=0; sum=0;

for (int i=1;i<=m;i++)

{

q[i].r++;

while (q[i].l<l) { l--; add(l); }

while (r<q[i].r) { r++; add(r); }

while (l<q[i].l) { del(l); l++; }

while (q[i].r<r) { del(r); r--; }

ans[q[i].id]=sum;

}

}

int main()

{

scanf("%lld",&md);

scanf("%s",st+1);

n=strlen(st+1);

ycl();

scanf("%d",&m);

for (int i=1;i<=m;i++) { scanf("%d%d",&q[i].l,&q[i].r); q[i].id=i;}

sort(q+1,q+m+1,cmp);

if (md==2||md==5) solve_25(); else solve_p();

for (int i=1;i<=m;i++) printf("%lld\n",ans[i]); 

return 0;

}