hdu 1238 Substrings(kmp+暴力枚举)

Problem Description

You are given a number of case-sensitive strings of alphabetic characters, find the largest string X, such that either X, or its inverse can be found as a substring of any of the given strings.

 

Input

The first line of the input file contains a single integer t (1 <= t <= 10), the number of test cases, followed by the input data for each test case. The first line of each test case contains a single integer n (1 <= n <= 100), the number of given strings, followed by n lines, each representing one string of minimum length 1 and maximum length 100. There is no extra white space before and after a string. 

 

Output

There should be one line per test case containing the length of the largest string found.

 

Sample Input

2

3 

ABCD

BCDFF

BRCD

2

rose

orchid

 

Sample Output

2

2

题意&思路：和poj 3080 类似

 

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<string>
#include<vector>
#include<stack>
#include<bitset>
#include<cstdlib>
#include<cmath>
#include<set>
#include<list>
#include<deque>
#include<map>
#include<queue>
#define ll long long int
using namespace std;
inline ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
inline ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
int moth[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int dir[4][2]={1,0 ,0,1 ,-1,0 ,0,-1};
int dirs[8][2]={1,0 ,0,1 ,-1,0 ,0,-1, -1,-1 ,-1,1 ,1,-1 ,1,1};
const int inf=0x3f3f3f3f;
const ll mod=1e9+7;
int nextt[107];
bool vis[207];
void getnext(string s){
    nextt[1]=0;
    int len=s.length();
    for(int i=2,j=0;i<=len;i++){
        while(j>0&&s[i-1]!=s[j]) j=nextt[j];
        if(s[i-1]==s[j]) j++;
        nextt[i]=j;
    }
}
bool kmp(string t,string p){
    int len1=p.length();
    int len2=t.length();
    for(int i=1,j=0;i<=len1;i++){
        while(j>0&&p[i-1]!=t[j]) j=nextt[j];
        if(p[i-1]==t[j]) j++;
        if(j==len2)
        return true;
    }
    return false;
}
string s[207];
int main(){
    ios::sync_with_stdio(false);
    int t;
    cin>>t;
    while(t--){
        int n;
        cin>>n;
        for(int i=1;i<=n;i++)
            cin>>s[i];
        int len=s[1].length();
        //cout<<len<<endl;
        int ans=0;
        for(int i=1;i<=len;i++){
            for(int j=0;j<=len-i;j++){
                string temp=s[1].substr(j,i);
                getnext(temp);
                bool f=1;
                for(int k=1;k<=n;k++){
                    string pre=s[k];
                    if(kmp(temp,pre)) continue;
                    reverse(pre.begin(),pre.end());
                    if(kmp(temp,pre)) continue;
                    f=0;
                    break;
                }
                if(f) ans=max(ans,i);
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}