hust1010 The Minimum Length

题目描述 There is a string A. The length of A is less than 1,000,000. I rewrite it again and again. Then I got a new string: AAAAAA...... Now I cut it from two different position and get a new string B. Then, give you the string B, can you tell me the length of the shortest possible string A. For example, A="abcdefg". I got abcdefgabcdefgabcdefgabcdefg.... Then I cut the red part: efgabcdefgabcde as string B. From B, you should find out the shortest A. 输入 Multiply Test Cases. For each line there is a string B which contains only lowercase and uppercase charactors. The length of B is no more than 1,000,000. 输出 For each line, output an integer, as described above. 样例输入

bcabcab
efgabcdefgabcde

样例输出

3

7

这题就是找最小的循环节是多少，直接用len-next[len]就行了。这里补充下next[i]的含义：1.指的是前i个字符前缀和后缀相同的匹配值。2.指的是如果s[i]不匹配，那么下一个要和当前字母匹配的字母的位置。next[i]，i的范围是[0,n]，不是[0,n-1].

#include<stdio.h>
#include<string.h>
char s[1000006];
int len,next[1000006];
void nextt()
{
	int i,j;
	i=0;j=-1;
	memset(next,-1,sizeof(next));
	while(i<len){
		if(j==-1 || s[i]==s[j]){
			i++;j++;next[i]=j;
		}
		else j=next[j];
	}
}

int main()
{
	int n,m,i,j,T;
	while(scanf("%s",s)!=EOF)
	{
		len=strlen(s);
		nextt();
		printf("%d\n",len-next[len]);
	}
	return 0;
}