hdu 3518 Boring counting（后缀数组+height分组）

题意：求重复但不重叠的子串数。

解题思路：height分组。枚举长度L，将height数组进行分组，使得每一组的height都大于L，若有一组的最大的sa值和最小的sa值之差大于L，则说明该组内存在一个符合条件的子串。

/*
 *Author:       Zhaofa Fang
 *Created time: 2013-05-06-19.28
 *Language:     C++
 */
#include <cstdio>
#include <cstdlib>
#include <sstream>
#include <iostream>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <string>
#include <utility>
#include <vector>
#include <queue>
#include <map>
#include <set>
using namespace std;

typedef long long ll;
#define DEBUG(x) cout<< #x << ':' << x << endl
#define FOR(i,s,t) for(int i = (s);i <= (t);i++)
#define FORD(i,s,t) for(int i = (s);i >= (t);i--)
#define REP(i,n) for(int i=0;i<n;i++)
#define REPD(i,n) for(int i=n-1;i>=0;i--)
#define PII pair<int,int>
#define PB push_back
#define MP make_pair
#define ft first
#define sd second
#define lowbit(x) (x&(-x))
#define INF (1<<30)


const int maxn = 1011;
char s[maxn];
int sa[maxn],t1[maxn],t2[maxn],c[maxn];
int rank[maxn],height[maxn];

void getHeight(int n){
    int k = 0;
    for(int i=1;i<=n;i++)rank[sa[i]] = i;
    for(int i=0;i<n;i++){
        if(k)k--;
        int j = sa[rank[i]-1];
        while(s[i+k] == s[j+k])k++;
        height[rank[i]] = k;
    }
}
bool cmp(int *r,int a,int b,int l){
    return (r[a] == r[b] && r[a+l]==r[b+l]);
}
void build_sa(int m,int n){
    int i,*x=t1,*y=t2,k,p;
    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,p=0;p<n;m=p,k<<=1){
        p=0;
        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;
        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];
        swap(x,y);
        p = 1; x[sa[0]] = 0;
        for(i=1;i<n;i++)
            x[sa[i]] = cmp(y,sa[i-1],sa[i],k)?p-1:p++;
    }
    getHeight(n-1);
}
int solve(int n){
    int ans = 0;
    for(int i=1;i<=n/2;i++){
        int mi = sa[1],mx = sa[1];
        for(int j=2;j<=n+1;j++){
            if(j!=n+1 && height[j]>=i){
                mi = min(mi,sa[j]);
                mx = max(mx,sa[j]);
            }else {
                if(mx - mi >= i)ans++;
                mx = mi = sa[j];
            }
        }
    }
    return ans;
}
int main(){
    //freopen("in","r",stdin);
    //freopen("out","w",stdout);
    while(gets(s)){
        if(s[0] == '#')break;
        int n = strlen(s);
        REP(i,n)s[i] = s[i] - 'a' + 1;
        build_sa(28,n+1);
        printf("%d\n",solve(n));
    }
    return 0;
}