poj3080 kmp+枚举

kmp算法+枚举 0ms

注意字典序输出，因为这个原因wrong了一次。

代码：

#include <iostream>
using namespace std;
#define LEN 60
int next[LEN];
char dna[11][LEN];

void get_next( char *a, int len )
{
	int i,temp;
    memset(next,0,sizeof(next));
	
	for( i = 1; i < len; i++ )
	{
		temp = next[i-1];
		while( temp && a[i] != a[temp] )
			temp = next[temp-1];
		if( a[i] == a[temp] )
			next[i] = temp+1;
	}
}
bool check( char *a, int len, int size )
{
	int i,j,k;
	get_next(a,len);
	
	for( k = 1; k < size; k++ )
	{
		j = 0;
		for( i = 0; i < LEN; i++ )
		{
			while( j > 0 && dna[k][i] != a[j] )
				j = next[j-1];
			if( dna[k][i] == a[j] )
			{ 
				if( j == len-1 ) break;
				else j++;
			}
			else j = 0;
		}
		if( j < len-1 ) return false;
	}
	return true;
}
int main()
{
	int cas,n;
    int i,j,len;
    bool flag;
    int start,l;
	char *temp;

	cin >> cas;
	while( cas-- )
	{
		cin >> n;
		for( i = 0; i < n; i++ ){
            cin >> dna[i];
		}
		flag = false;
		len = LEN;
        while( len>=3 && !flag )
		{
			j = 0;
			for( i = 0;;i++ ){
				if( i+len <= LEN ){
					if( check(&dna[0][i],len,n) ){
						flag = true;
						if( j == 0 || strncmp(&dna[0][i],temp,len) < 0 ){
							temp = &dna[0][i];
							start = i;
							l = len;
							j++;
						}
					}
				}
				else break;
			}
			len--;
		}
		if(flag){
			for( i = start; i < start+l; i++ )
				cout << dna[0][i];
			cout << endl;
		}
		else cout << "no significant commonalities" << endl;
	}
	return 0;
}