POJ 3261 suffix array find substrings that appear repeatedly k (substrings can overlap)

Title: http://poj.org/problem?id=3261

is still a typical application of the suffix array----suffix array +lcp+ two points

That's pretty smooth, 1A.

But most of the time is debugging code. Because the template's global variables are mixed, and you forget it. ,, and so on Xi ' an invitational tournament and four provinces after the end of the calm reflection under the attempt to please template

Error: 1, k with the wrong, the title of K and the template K mixed;

2, or the second part of the C () function, this in fact, in front of a "POJ 1226 Hdu 1238 substrings to find a number of string strings and crossdress the longest common substring 2002 Asian Tianjin Pre-selected topic" C functions almost identical. But it's easier than that, but it's been a while. ，。 At the start. If RET is not recorded, the maximum value of RET should be recorded.

3,last>=kk-1 only, because Lcp[i] itself is two substrings of the public prefix length

int C (int x) {    int ret=0,last=0;    for (int i=0;i<=n;i++)    {        if (lcp[i]>=x) ret++;        else        {            Last=max (last,ret);            ret=0;        }    }    if (last>=kk-1) return 1;    else return 0;}

On the code:

#include <cstdio> #include <iostream> #include <string> #include <algorithm>using namespace std ; const int MAXN = 20200;int rk[maxn],sa[maxn],s[maxn],tmp[maxn],lcp[maxn],n,k,kk;bool cmpsa (int i,int j) {if (Rk[i]! = R    K[J]) return rk[i]<rk[j];        else {int ri = i+k<=n?rk[i+k]:-1;        int RJ = j+k<=n?rk[j+k]:-1;    Return ri<rj;    }}void Consa () {for (int i=0;i<=n;i++) sa[i]=i,rk[i]=i<n?s[i]:-1;        for (k=1;k<=n;k*=2) {sort (SA,SA+N+1,CMPSA);        tmp[sa[0]]=0;        for (int i=1;i<=n;i++) {tmp[sa[i]]=tmp[sa[i-1]]+ (CMPSA (Sa[i-1],sa[i])? 1:0);    } for (int i=0;i<=n;i++) rk[i]=tmp[i];    }}void CONSTRUCT_LCP () {//n=strlen (s);    for (int i=0; i<=n; i++) rk[sa[i]]=i;    int h=0;    lcp[0]=0;        for (int i=0;i<n;i++) {int j=sa[rk[i]-1];        if (h>0) h--;  for (; J+h<n && i+h<n; h++) {if (s[j+h]!=s[i+h]) break;      } lcp[rk[i]-1]=h;    }}int C (int x) {int ret=0,last=0;        for (int i=0;i<=n;i++) {if (lcp[i]>=x) ret++;            else {Last=max (Last,ret);        ret=0;    }} if (last>=kk-1) return 1; else return 0;}    int main () {//freopen ("Poj 3261.txt", "R", stdin);        while (scanf ("%d%d", &n,&kk)!=eof) {for (int i=0;i<n;i++) scanf ("%d", &s[i]);        S[n]=-1;        Consa ();        CONSTRUCT_LCP ();        int d=0,up=n+1,mid;            while (up>d+1) {mid= (d+up)/2;            if (C (mid)) D=mid;        else Up=mid;    } printf ("%d\n", D); } return 0;}

POJ 3261 suffix array find substrings that appear repeatedly k (substrings can overlap)