最字头之三：最长重复子串

在之前的博文已经有记录，只记录代码。

最简单的算法：

#include <iostream>
#include <string>
using namespace std;
int length(char* p,char* q){
   int len = 1;
   //if(*p == *q) len++;
   while(*p++ == *q++ && *p && *q)//后面的q和p已经经前面的++计算了
   len++;
   return len;
}
int main(){
   int index = 0;
   int maxlen = 0;
   string s = "caixiaorangdianzancaixiaorang";
   for(int i = 0; i < s.size(); i++){
      for(int j = i + 1; j < s.size(); j++){
	      if(s[i] == s[j]){
		     int len = length(&s[i],&s[j]);
			 if(len > maxlen){
			   maxlen = len;
			   index = i;
			 }
		  }
	  }
   }
   for(int i = index; i < index + maxlen; i++)
   cout << s[i];
   cout << endl;
   return 0;
}

后缀数组方法：

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int comlen(string s1,string s2){
   int i = 0;
   int len = 0;
   while(s1[i] == s2[i]){
      len ++;
	  i++;
   }
   return len;
}
int main(){
   int index = 0;
   int maxlen = 0;
   string s = "caixiaorangabcdcaixiaorang";
   string suf[30];
   for(int i = s.size()-1; i >= 0; i--){
      suf[i] = s.substr(i,s.size()-i);
   }
   sort(suf,suf+s.size());
   //for(int i = 0; i < suf.size(); i++)
   //cout << suf[i] << endl;
   for(int i = 0; i < s.size(); i++){
      int tmp = comlen(suf[i],suf[i+1]);
	  if(tmp > maxlen){
	    maxlen = tmp;
		index = i;
	  }
   }
   cout << suf[index] << endl;
   return 0;
}

后缀树法（Trie树）：

略