## 12206 - Stammering Aliens

All about problems in Volume 122. If there is a thread about your problem, please use it. If not, create one with its number in the subject.

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fsps60312
New poster
Posts: 16
Joined: Sun Jan 25, 2015 5:46 pm

### Re: 12206 - Stammering Aliens

Why getting WA? I generated more than 3000 cases randomly and find nothing different in output file with AC code. Are there any tricky cases? Please help me
This is my code:

Code: Select all

``````#include<cstdio>
#include<cstdlib>
int n,m,sa[40001],t1[3][40001],rank[40001],height[40001];
char S[40001];
void getsa()
{
int i,*x=t1[0],*y=t1[1],*c=t1[2];
int l='z'+1;
for(i=0;i<l;i++)c[i]=0;
for(i=0;i<n;i++)c[x[i]=S[i]]++;
for(i=1;i<l;i++)c[i]+=c[i-1];
for(i=n-1;i>=0;i--)sa[--c[x[i]]]=i;
for(int k=1;k<=n;k<<=1)
{
int 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;//sort second value
for(i=0;i<l;i++)c[i]=0;
for(i=0;i<n;i++)c[x[i]]++;
for(i=1;i<l;i++)c[i]+=c[i-1];
for(i=n-1;i>=0;i--)sa[--c[x[y[i]]]]=y[i];//sort by first->second
int *tmp=x;x=y,y=tmp;
p=1,x[sa[0]]=0;
for(i=1;i<n;i++)x[sa[i]]=y[sa[i]]==y[sa[i-1]]&&y[sa[i]+k]==y[sa[i-1]+k]?p-1:p++;
if(p>=n)break;
l=p;
}
}
void getheight()
{
int i,k=0;
for(i=0;i<n;i++)rank[sa[i]]=i;
for(i=0;i<n;i++)
{
if(k)k--;
if(!rank[i])continue;
int j=sa[rank[i]-1];
while(S[i+k]==S[j+k])k++;
height[rank[i]]=k;
}
}
int pos;
bool isans(int hv)
{
int ans=1,tpos=sa[0];
pos=-1;
for(int i=1;i<n;i++)
{
if(height[i]>=hv)
{
ans++;
if(sa[i]>tpos)tpos=sa[i];
if(ans>=m&&tpos>pos)pos=tpos;
}
else ans=1,tpos=sa[i];
}
return pos>=0;
}
int getans()
{
int l=1,r=n+1;
while(l<r)
{
int mid=(l+r)/2;
if(isans(mid))l=mid+1;
else r=mid;
}
if(r-1)isans(r-1);
return r-1;
}
int main()
{
//freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);
while(scanf("%d",&m)==1&&m)
{
scanf("%s",S);
n=-1;while(S[++n]);
if(m==1){printf("%d 0\n",n);continue;}
getsa();
getheight();
//printf("height:");for(int i=0;i<n;i++)printf(" %d",height[i]);printf("\n");
int ans=getans();
if(ans)printf("%d %d\n",ans,pos);
else printf("none\n");
}
return 0;
}``````

fsps60312
New poster
Posts: 16
Joined: Sun Jan 25, 2015 5:46 pm

### Re: 12206 - Stammering Aliens

YEAH!!! Finally solved!

Repon kumar Roy
Learning poster
Posts: 96
Joined: Tue Apr 23, 2013 12:54 pm

### Re: 12206 - Stammering Aliens

Suffix-Array & RMQ
Thinks get AC