csu 1305 Substring （后缀数组）

http://acm.csu.edu.cn/OnlineJudge/problem.php?id=1305

1305: Substring

Time Limit: 2 Sec  Memory Limit: 10 MB Submit: 12  Solved: 2 [Submit][Status][Web Board]

Description

Given a string s. The length of s is smaller than 1000. You are to caculate the number of different substrings of s.

Input

There are multiple test cases. Each test case contains one line, with a string s.You may assume that s only contains lowercase letters. You may assume that there are only ten test cases with the length of string s is bigger than 400.

Output

For each test case, you are only to output one integer,  the answer.

Sample Input

a
ac
abcd

Sample Output

1
3
10

【题解】：
后缀数组：用（1+2+。。。+len）-（height数组之后）
【code】：

 #include <iostream>
 #include<string.h>
 #include<stdio.h>

 using namespace std;

 #define maxn 10100
 #define cls(x) memset(x, 0, sizeof(x))
 int wa[maxn],wb[maxn],wv[maxn],wss[maxn];
 int cmp(int *r,int a,int b,int l)
 {return r[a]==r[b]&&r[a+l]==r[b+l];}

 void da(char *r,int *sa,int n,int m)
 {
      cls(wa);
      cls(wb);
      cls(wv);
      cls(wss);
      int i,j,p,*x=wa,*y=wb,*t;
      for(i=;i<m;i++) wss[i]=;
      for(i=;i<n;i++) wss[x[i]=r[i]]++;
      for(i=;i<m;i++) wss[i]+=wss[i-];
      for(i=n-;i>=;i--) sa[--wss[x[i]]]=i;
      for(j=,p=;p<n;j*=,m=p)
      {
        for(p=,i=n-j;i<n;i++) y[p++]=i;
        for(i=;i<n;i++) if(sa[i]>=j) y[p++]=sa[i]-j;
        for(i=;i<n;i++) wv[i]=x[y[i]];
        for(i=;i<m;i++) wss[i]=;
        for(i=;i<n;i++) wss[wv[i]]++;
        for(i=;i<m;i++) wss[i]+=wss[i-];
        for(i=n-;i>=;i--) sa[--wss[wv[i]]]=y[i];
        for(t=x,x=y,y=t,p=,x[sa[]]=,i=;i<n;i++)
        x[sa[i]]=cmp(y,sa[i-],sa[i],j)?p-:p++;
      }
      return;
 }
 int rank[maxn],height[maxn];
 void calheight(char *r,int *sa,int n)
 {
      cls(rank);
      cls(height);
      int i,j,k=;
      for(i=;i<n;i++) rank[sa[i]]=i;
      for(i=;i<n;height[rank[i++]]=k)
      for(k?k--:,j=sa[rank[i]-];r[i+k]==r[j+k]&&i!=j;k++);
      return;
 }

 char ca[maxn * ];
 int sa[maxn];

 int main()
 {
     while (cin >> ca)
     {
         int len = strlen(ca);
         da(ca, sa, len+, );
         calheight(ca,sa,len+);
         int i,sum=;
         for(i=;i<=len;i++)
         {
             sum+=height[i];
         }
         cout<<len*(len+)/-sum<<endl;
         cls(ca);
     }
     return ;
 }