Hdu 6194 String string string (suffix array)

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Test instructions

Give you a string, give you a K, ask you how many substrings happen to occur in the original string k times.

Exercises

After the suffix array is calculated, use the information of the height array to find the answer.

Each time an interval of k length is used to get the height array of the card, the LCP of the interval is obtained.

The contribution of this interval is Ans=lcp-max (Height[i],height[i+k]).

If ans<=0, it does not contribute.

Like 2 AAA.

The suffix array is:

1 A

2 AA

3 AAA

Height is 0,1,2

Now sweep to [1,2],lcp=1,max (Height[i],height[i+k]) =2,ans=-1, so this interval does not contribute

to [2,3],lcp=2,max (Height[i],height[i+k]) =1,ans=1, so the interval contributes 1.

1#include <bits/stdc++.h>2 #defineF (I,A,B) for (int i=a;i<=b;++i)3 using namespacestd;4 5 namespacesuffixarray{6     #defineFN (n) for (int i=0;i<n;i++)7     Const intN =1e5+7;8     intRnk[n],sa[n],height[n],c[n];CharS[n];9     voidGetsa (intNintMint*X=RNK,int*y=height) {TenFN (m) c[i]=0; FN (n) c[x[i]=s[i]]++; FN (m) c[i+1]+=C[i]; One          for(inti=n-1; i>=0; i--) sa[--c[x[i]]]=i; A          for(intk=1, p;p=0, K<=n;k=p>=n? n:k<<1, m=p) { -              for(inti=n-k;i<n;i++) y[p++]=i; -FN (N)if(sa[i]>=k) y[p++]=sa[i]-K; theFN (m) c[i]=0; FN (n) c[x[y[i]]]++; FN (m) c[i+1]+=C[i]; -              for(inti=n-1; i>=0; i--) sa[--c[x[y[i]]]]=Y[i]; -Swap (x, y), p=1, x[sa[0]]=0; -              for(intI=1; i<n;i++) +x[sa[i]]=y[sa[i-1]]==y[sa[i]]&&y[sa[i-1]+k]==y[sa[i]+k]?p-1:p + +; -         } +FN (n) rnk[sa[i]]=i; A          for(intI=0, j,k=0; i<n-1; height[rnk[i++]]=k) at          for(k=k?k-1: k,j=sa[rnk[i]-1];s[i+k]==s[j+k];k++); -     } - } - using namespaceSuffixarray; -  - intt,k,n,f[n][ -]; in  - voidRmqint*a) to { +      for(intI=1; i<=n;i++) f[i][0]=A[i]; -      for(intj=1;1<<j<n;j++) for(intI=1; i<=n;i++) the     if(I+ (1&LT;&LT;J)-1<=n) F[i][j]=min (f[i][j-1],f[i+ (1<<j-1)][j-1]); *     Else  Break; $ }Panax NotoginsengInlineintFindintLintR) - { the     intk= to-__BUILTIN_CLZ (r-l+1); +     returnMin (f[l][k],f[r-(1&LT;&LT;K) +1][k]); A } the  + intMain () - { $scanf"%d",&t); $      while(t--) -     { -scanf"%d%s",&k,s); theN=strlen (s), Getsa (n+1, -); -height[n+1]=0; rmq (height);Wuyi         intans=0; theF (I,1, N) -         { Wu             if(i+k-1>n)Continue; -             intLCP; About             if(i+1>i+k-1) lcp=n-Sa[i]; $             ElseLcp=find (i+1, i+k-1); -Lcp-=max (height[i],height[i+K]); -             if(lcp<=0)Continue; -ans+=LCP; A         } +printf"%d\n", ans); the     } -     return 0; $}

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Hdu 6194 String string string (suffix array)