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=0;i<m;i++) wss[i]=0;
     for(i=0;i<n;i++) wss[x[i]=r[i]]++;
     for(i=1;i<m;i++) wss[i]+=wss[i-1];
     for(i=n-1;i>=0;i--) sa[--wss[x[i]]]=i;
     for(j=1,p=1;p<n;j*=2,m=p)
     {
       for(p=0,i=n-j;i<n;i++) y[p++]=i;
       for(i=0;i<n;i++) if(sa[i]>=j) y[p++]=sa[i]-j;
       for(i=0;i<n;i++) wv[i]=x[y[i]];
       for(i=0;i<m;i++) wss[i]=0;
       for(i=0;i<n;i++) wss[wv[i]]++;
       for(i=1;i<m;i++) wss[i]+=wss[i-1];
       for(i=n-1;i>=0;i--) sa[--wss[wv[i]]]=y[i];
       for(t=x,x=y,y=t,p=1,x[sa[0]]=0,i=1;i<n;i++)
       x[sa[i]]=cmp(y,sa[i-1],sa[i],j)?p-1:p++;
     }
     return;
}
int rank[maxn],height[maxn];
void calheight(char *r,int *sa,int n)
{
     cls(rank);
     cls(height);
     int i,j,k=0;
     for(i=1;i<n;i++) rank[sa[i]]=i;
     for(i=0;i<n;height[rank[i++]]=k)
     for(k?k--:0,j=sa[rank[i]-1];r[i+k]==r[j+k]&&i!=j;k++);
     return;
}

char ca[maxn * 2];
int sa[maxn];

int main()
{
    while (cin >> ca)
    {
        int len = strlen(ca);
        da(ca, sa, len+1, 130);
        calheight(ca,sa,len+1);
        int i,sum=0;
        for(i=1;i<=len;i++)
        {
            sum+=height[i];
        }
        cout<<len*(len+1)/2-sum<<endl;
        cls(ca);
    }
    return 0;
}