HDU-4691 Front compression 后缀数组

　　题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4691

　　后缀数组模板题，求出Height数组后，对Height做RMQ，然后直接统计就可以了。。。

//STATUS:C++_AC_828MS_11284KB
#include <functional>
#include <algorithm>
#include <iostream>
//#include <ext/rope>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <numeric>
#include <cstring>
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
#include <bitset>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <list>
#include <set>
#include <map>
using namespace std;
//#pragma comment(linker,"/STACK:102400000,102400000")
//using namespace __gnu_cxx;
//define
#define pii pair<int,int>
#define mem(a,b) memset(a,b,sizeof(a))
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define PI acos(-1.0)
//typedef
typedef __int64 LL;
typedef unsigned __int64 ULL;
//const
const int N=100010;
const int INF=0x3f3f3f3f;
const int MOD=1000000007,STA=8000010;
const LL LNF=1LL<<60;
const double EPS=1e-8;
const double OO=1e15;
const int dx[4]={-1,0,1,0};
const int dy[4]={0,1,0,-1};
const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
//Daily Use ...
inline int sign(double x){return (x>EPS)-(x<-EPS);}
template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
template<class T> inline T Min(T a,T b){return a<b?a:b;}
template<class T> inline T Max(T a,T b){return a>b?a:b;}
template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
//End

char s[N];
int d[N][20];
int num[N];
int sa[N],t1[N],t2[N],c[N],rank[N],height[N];
int n,m;

void build_sa(int s[],int n,int m)
{
    int i,k,p,*x=t1,*y=t2;
    //第一轮基数排序
    for(i=0;i<m;i++)c[i]=0;
    for(i=0;i<n;i++)c[x[i]=s[i]]++;
    for(i=1;i<m;i++)c[i]+=c[i-1];
    for(i=n-1;i>=0;i--)sa[--c[x[i]]]=i;
    for(k=1;k<=n;k<<=1){
        p=0;
        //直接利用sa数组排序第二关键字
        for(i=n-k;i<n;i++)y[p++]=i;
        for(i=0;i<n;i++)if(sa[i]>=k)y[p++]=sa[i]-k;
        //基数排序第一关键字
        for(i=0;i<m;i++)c[i]=0;
        for(i=0;i<n;i++)c[x[y[i]]]++;
        for(i=1;i<m;i++)c[i]+=c[i-1];
        for(i=n-1;i>=0;i--)sa[--c[x[y[i]]]]=y[i];
        //根据sa和x数组计算新的x数组
        swap(x,y);
        p=1;x[sa[0]]=0;
        for(i=1;i<n;i++)
            x[sa[i]]=y[sa[i-1]]==y[sa[i]] && y[sa[i-1]+k]==y[sa[i]+k]?p-1:p++;
        if(p>=n)break;   //已经排好序，直接退出
        m=p;     //下次基数排序的最大值
    }
}

void getHeight(int s[],int n)
{
    int i,j,k=0;
    for(i=0;i<=n;i++)rank[sa[i]]=i;
    for(i=0;i<n;i++){
        if(k)k--;
        j=sa[rank[i]-1];
        while(s[i+k]==s[j+k])k++;
        height[rank[i]]=k;
    }
}

void rmq_init(int a[])
{
    int i,j;
    for(i=1;i<=n;i++)d[i][0]=a[i];
    for(j=1;(1<<j)<=n;j++){
        for(i=1;i+(1<<j)-1<=n;i++){
            d[i][j]=Min(d[i][j-1],d[i+(1<<(j-1))][j-1]);
        }
    }
}

int rmq(int l,int r)
{
    int k=0;
    while((1<<(k+1))<=r-l+1)k++;
    return Min(d[l][k],d[r-(1<<k)+1][k]);
}

int lcp(int a,int b)
{
    if(a==b)return n-a;      //a和b为同一后缀，直接输出，字串串长度为n
    int ra=rank[a],rb=rank[b];
    if(ra>rb)swap(ra,rb);
    return rmq(ra+1,rb);
}

int w[N];

int main(){
 //   freopen("in.txt","r",stdin);
    int i,j,k,Q,a,b,la,lb;
    LL ans1,ans2,t;
    w[0]=1;
    for(i=k=1;i<N;i=j,k++)
        for(j=i*10;i<j && i<N;i++)w[i]=k;
    while(~scanf("%s",s))
    {
        n=strlen(s);
        for(i=0;i<n;i++)
            num[i]=s[i]-'a'+1;
        num[n]=0;m=27;
        build_sa(num,n+1,m);
        getHeight(num,n);
        rmq_init(height);

        scanf("%d",&Q);
        ans1=(LL)Q,ans2=(LL)2*Q;
        scanf("%d%d",&la,&lb);
        ans1+=(LL)lb-la;ans2+=(LL)lb-la+1;
        while(--Q){
            scanf("%d%d",&a,&b);
            ans1+=(LL)b-a;
            t=(LL)Min(lcp(la,a),lb-la,b-a);
            ans2+=(LL)b-a-t+w[t];
        //    printf("  %I64d %d %d %d
",t,lcp(la,a),lb-la,b-a);
            la=a;lb=b;
        }

        printf("%I64d %I64d
",ans1,ans2);

    }
    return 0;
}