傳送門:http://acm.hdu.edu.cn/showproblem.php?pid=3746
Cyclic Nacklace
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 9963 Accepted Submission(s): 4257
As Christmas is around the corner, Boys are busy in choosing christmas presents to send to their girlfriends. It is believed that chain bracelet is a good choice. However, Things are not always so simple, as is known to everyone, girl's fond of the colorful decoration to make bracelet appears vivid and lively, meanwhile they want to display their mature side as college students. after CC understands the girls demands, he intends to sell the chain bracelet called CharmBracelet. The CharmBracelet is made up with colorful pearls to show girls' lively, and the most important thing is that it must be connected by a cyclic chain which means the color of pearls are cyclic connected from the left to right. And the cyclic count must be more than one. If you connect the leftmost pearl and the rightmost pearl of such chain, you can make a CharmBracelet. Just like the pictrue below, this CharmBracelet's cycle is 9 and its cyclic count is 2:
Now CC has brought in some ordinary bracelet chains, he wants to buy minimum number of pearls to make CharmBracelets so that he can save more money. but when remaking the bracelet, he can only add color pearls to the left end and right end of the chain, that is to say, adding to the middle is forbidden.
CC is satisfied with his ideas and ask you for help.
Each test case contains only one line describe the original ordinary chain to be remade. Each character in the string stands for one pearl and there are 26 kinds of pearls being described by 'a' ~'z' characters. The length of the string Len: ( 3 <= Len <= 100000 ).
題意:給出一個字符串,問在首尾添加多少個字符可以形成至少2個循環 如 abca 需要添加 bc 纔可以
解題:用KMP裏面的next數組,找個字符串多實驗幾遍就可以得出怎樣輸出了
#include<cstdio>
#include<cstring>
char s[100010];
int next[100010],len;
void Next()
{
int i=0,j=-1;
next[0]=-1;
while(i<len)
{
if(s[i]==s[j]||j==-1)
next[++i]=++j;
else
j=next[j];
}
}
int main()
{
int T;
scanf("%d",&T);
while(T--)
{
scanf("%s",s);
len=strlen(s);
Next();
int l=len-next[len]; //循環節長度
if(len%(len-next[len])==0&&len!=len-next[len])
printf("0\n");
else
printf("%d\n",l-len%(len-next[len])); //找個字符串試驗試驗就可以了
}
return 0;
}
// 實驗 ababa abcab
/*void Kmp()
{
int i=0,j=0;
while(i<len)
{
if(s[i]==next[j]||j==-1)
{
i++;j++;
}
else
j=next[j];
if(j==len2)
{
sum++;
j=0;
}
}
}*/