You're Given a String... (kmp)

You're Given a String...

You're given a string of lower-case Latin letters. Your task is to find the length of its longest substring that can be met in the string at least twice. These occurrences can overlap (see sample test 2).
Input The first input line contains the string. It's guaranteed, that the string is non-empty, consists of lower-case Latin letters, and its length doesn't exceed 100.
Output Output one number — length of the longest substring that can be met in the string at least twice.
Example Input

abcd

Output

0

Input

ababa

Output

3

Input

zzz

Output

2

枚举子串，kmp匹配
code：#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
using namespace std;
const int MAXN = 110;
string s;
string w;
int Next[MAXN];
void getNext(){
int i = -1,j = 0;
int len = s.length();
memset(Next,0,sizeof(Next));
Next[0] = -1;
while(j < len){
if(i == -1 || w[i] == w[j]){
i++,j++;
Next[j] = i;
}
else
i = Next[i];
}
}
int kmp(){
int i = 0, j = 0,cnt = 0;
int lens = s.length();
int lenw = w.length();
getNext();
while(j < lens){
if(i == -1 || w[i] == s[j])
i++,j++;
else
i = Next[i];
if(i == lenw)
cnt++;
}
return cnt;
}
int main(){
int i,j;
int ans = 0;
cin >> s;
for(i = 0; i < s.length(); i++){
for(j = i; j < s.length(); j++){
w = s.substr(i,j-i+1);
if(kmp() >= 2){
int len = j-i+1;
ans = max(ans,len);
}
}
}
cout << ans << endl;
return 0;
}