【HAOI2017】供给侧改革

题面

https://www.luogu.org/problem/P3732

题解

// luogu-judger-enable-o2
#include<cstdio>
#include<iostream>
#include<cstring>
#include<set>
#include<algorithm>
#include<vector>
#define ri register int
#define N 100500
using namespace std;

int n,q,cc;
long long ans[N];
char s[N];

struct ques {
  int l,r,id;
  bool operator < (const ques &rhs) const {
    return r<rhs.r || (r==rhs.r && l<rhs.l);
  }
} qu[N];

struct pir{
  int l,r,v;
  bool operator < (const pir &rhs) const {
    return r<rhs.r || (r==rhs.r && l<rhs.l);
  }
} pp[N<<5];

struct SAM{
  int ch[N<<1][2];
  int ff[N<<1],len[N<<1];
  int las,tot;
  vector<int> son[N<<1];
  set<int> endp[N<<1];
  void clear() {las=tot=1;}
  void extend(int c){
    int p=las,np=++tot; las=tot;
    len[np]=len[p]+1;
    while (p && ch[p][c]==0) ch[p][c]=np,p=ff[p];
    if (!p) {
      ff[np]=1;
    }
    else {
      int q=ch[p][c];
      if (len[q]==len[p]+1) {
        ff[np]=q;
      }
      else {
        int nq=++tot;
        len[nq]=len[p]+1; ff[nq]=ff[q];
        for (ri i=0;i<2;i++) ch[nq][i]=ch[q][i];
        ff[np]=ff[q]=nq;
        while (p && ch[p][c]==q) ch[p][c]=nq,p=ff[p];
      }
    }
    endp[np].insert(n-len[np]+1);
  }
  void maketree() {
    for (ri i=1;i<=tot;i++) son[ff[i]].push_back(i);
  }
  void merge(int x) {
    set<int> :: iterator it,it2,itp,itq;
    for (ri i=0;i<son[x].size();i++) {
      merge(son[x][i]);
      if (endp[x].size()<endp[son[x][i]].size()) swap(endp[x],endp[son[x][i]]);
      for (it=endp[son[x][i]].begin();it!=endp[son[x][i]].end();++it) {
        endp[x].insert(*it);
        it2=endp[x].lower_bound(*it);
        itq=itp=it2;
        if (itp!=endp[x].begin()) {
          --itp;
          pp[++cc]=(pir){*itp,*it,len[x]};
        }
        {
          itq++;
          if (itq!=endp[x].end()) pp[++cc]=(pir){*it,*itq,len[x]};
        }
        endp[x].erase(*it);
      }
      for (it=endp[son[x][i]].begin();it!=endp[son[x][i]].end();++it) endp[x].insert(*it);
    }
  }
} sam;

struct Fenwick{
  int Max[N<<2],Laz[N<<2];
  long long Sum[N<<2];
  
  int search(int x,int lb,int rb,int l,int r){
    if (l<=lb && rb<=r) return Max[x];
    if (lb>r || rb<l) return 0;
    else {
      int mid=(lb+rb)/2;
      return max(search(2*x,lb,mid,l,r),search(2*x+1,mid+1,rb,l,r));
    }
  }
  
  void in(int x,int lb,int rb,int loc,int v){
    if (lb==rb) {Max[x]=v;return;}
    int mid=(lb+rb)/2;
    if (loc<=mid) in(2*x,lb,mid,loc,v); else in(2*x+1,mid+1,rb,loc,v);
    Max[x]=max(Max[2*x],Max[2*x+1]);
  }
  
  int xia(int x,int lb,int rb,int v) {
    if (Max[x]<=v) return 0;
    if (lb==rb) return lb;
    int mid=(lb+rb)/2;
    if (Max[2*x+1]>v) return xia(2*x+1,mid+1,rb,v); else return xia(2*x,lb,mid,v);
  }
  
  int lowerbound(int x,int lb,int rb,int l,int r,int v) {
    if (l<=lb && rb<=r) return xia(x,lb,rb,v);
    if (lb>r || rb<l) return 0;
    int mid=(lb+rb)/2;
    int t=lowerbound(2*x+1,mid+1,rb,l,r,v);
    if (t) return t; else return lowerbound(2*x,lb,mid,l,r,v);
  }
  
  void pushdown(int x,int lb,int rb) {
    int v=Laz[x]; Laz[x]=0;
    int mid=(lb+rb)/2;
    Sum[2*x]=(mid-lb+1)*1LL*v,Laz[2*x]=v;
    Sum[2*x+1]=(rb-mid)*1LL*v,Laz[2*x+1]=v;
  }
  
  void ass(int x,int lb,int rb,int l,int r,int v){
    if (l<=lb && rb<=r) {
      Sum[x]=(rb-lb+1)*1LL*v;
      Laz[x]=v;
      return;
    }
    if (lb>r || rb<l) return;
    int mid=(lb+rb)/2;
    if (Laz[x]) pushdown(x,lb,rb);
    ass(2*x,lb,mid,l,r,v); ass(2*x+1,mid+1,rb,l,r,v);
    Sum[x]=Sum[2*x]+Sum[2*x+1];
  }
  
  void insert(int loc,int x) {
    if (search(1,1,n,loc,n)>=x) return;
    in(1,1,n,loc,x);
    int Lb=lowerbound(1,1,n,1,loc-1,x);
    ass(1,1,n,Lb+1,loc,x);
  }
  
  long long find(int x,int lb,int rb,int l,int r) {
    if (l<=lb && rb<=r) return Sum[x];
    if (lb>r || rb<l) return 0;
    else {
      if (Laz[x]) pushdown(x,lb,rb);
      int mid=(lb+rb)/2;
      return find(2*x,lb,mid,l,r)+find(2*x+1,mid+1,rb,l,r);
    }
  }
} fg;

int main(){
  scanf("%d %d",&n,&q);
  sam.clear();
  scanf("%s",s+1);
  int l=strlen(s+1);
  for (ri i=l;i>=1;i--) sam.extend(s[i]-'0');
  for (ri i=1;i<=q;i++) {
    scanf("%d %d",&qu[i].l,&qu[i].r);
    qu[i].id=i;
  }
  sam.maketree();
  cc=0; sam.merge(1);
  sort(qu+1,qu+q+1);
  sort(pp+1,pp+cc+1);
  int p=1;
  for (ri i=1;i<=q;i++) {
    while (pp[p].r<=qu[i].r && p<=cc) fg.insert(pp[p].l,pp[p].v),p++;
    ans[qu[i].id]=fg.find(1,1,n,qu[i].l,qu[i].r);
  }
  for (ri i=1;i<=q;i++) printf("%lld
",ans[i]);
  return 0;
}