poj 3415 Common Substrings

//#include<bits/stdc++.h>
#include<stdio.h>
#include<math.h>
#include<algorithm>
#include<string.h>

using namespace std;

#define N 200005
#define LL long long

int wa
,wb
,wm
,wv
,sa
;
int *rank,height
,s
,a
;
//sa:字典序中排第i位的起始位置在str中第sa[i]
//rank:就是str第i个位置的后缀是在字典序排第几
//height：字典序排i和i-1的后缀的最长公共前缀

bool cmp(int *r,int a,int b,int l)
{
return r[a] == r[b] && r[a+l] == r[b+l];
}

void getsa(int *r,int *sa,int n,int m)
{
int *x=wa,*y=wb,*t;
for(int i=0; i<m; ++i)wm[i]=0;
for(int i=0; i<n; ++i)wm[x[i]=r[i]]++;
for(int i=1; i<m; ++i)wm[i]+=wm[i-1];
for(int i=n-1; i>=0; --i)sa[--wm[x[i]]]=i;
for(int i=0,j=1,p=0; p<n; j=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<m; ++i)wm[i]=0;
for(i=0; i<n; ++i)wm[x[y[i]]]++;
for(i=1; i<m; ++i)wm[i]+=wm[i-1];
for(i=n-1; i>=0; --i)sa[--wm[x[y[i]]]]=y[i];
for(t=x,x=y,y=t,i=p=1,x[sa[0]]=0; i<n; ++i)
{
x[sa[i]]=cmp(y,sa[i],sa[i-1],j)?p-1:p++;
}
}
rank=x;
}

void getheight(int *r,int *sa,int n)
{
for(int i=0,j=0,k=0; i<n; height[rank[i++]]=k)
{
for(k?--k:0,j=sa[rank[i]-1]; r[i+k] == r[j+k]; ++k);
}
}
int k;
char s1
;
int len1;

LL solve(int n,int len,int k)
{
int *mark=wa,*sta=wb,top=0,i;
LL sum=0,num[3]= {0};
for(i = 1;i<=n;i++)
{
if(height[i]<k)
{
top = num[1] = num[2] =0;
}
else
{
for(int size = top; size&&sta[size]>height[i]-k+1; size--)
{
num[mark[size]] += height[i]-k+1-sta[size];
sta[size] = height[i]-k+1;
}
sta[++top] = height[i]-k+1;
if(sa[i-1]<len) mark[top] = 1;
if(sa[i-1]>len) mark[top] = 2;
num[mark[top]]+=height[i]-k+1;
if(sa[i]<len) sum+=num[2];
if(sa[i]>len) sum+=num[1];
}
}
return sum;
}

int main()
{
int i,j;
while(~scanf("%d",&k),k)
{
scanf("%s",s1);
int n = 0;
for(n = 0;s1
!='\0';n++)
s
= s1
;
s[len1=n] = '#';
scanf("%s",s1+n+1);
n++;
for(;s1
!='\0';n++)
s
= s1
;
s
= 0;
getsa(s,sa,n+1,201);
getheight(s,sa,n);
printf("%lld\n",solve(n,len1,k));
}
return 0;
}