秋季学期一起开心讲课-week03-kmp,马拉车，字典树

kmp模板：

void findnext(char *str,int *Next,int len)
{
	Next[0] = -1;
	int i = 0,j = -1;
	while(i<len)
	{
		if(str[i] == str[j]||j==-1)
			Next[++i] = ++j;
		else
			j = Next[j];
	}
}
int kmp(char *s,char *p)
{
	int Next[1000];
	int slen = strlen(s);
	int plen = pstrlen(p);
	findnext(p,Next,plen);
	int i = -1,j = -1;
	while(i<slen)
	{
		if(j==-1||s[i]==s[j])
		{
			i++;
			j++; 
		}
		else
			j = Next[j];
		if(j == plen)
			return i - plen;
	}
	return -1;
}

马拉车算法：

int Manacher(char *s) 
{ 
	int len=strlen(s+1); 
	for (int i=1;i<=len;i++) 
		now[2*i-1]='%',now[2*i]=s[i]; 
	now[len=len*2+1]='%'; 
	int pos=0,R=0; 
	for (int i=1;i<=len;i++) 
	{ 
		if (i<R) 
			p[i]=min(p[2*pos-i],R-i); 
		else 
			p[i]=1; 
		while (1<=i-p[i]&&i+p[i]<=len&&now[i-p[i]]==now[i+p[i]]) 
			p[i]++; 
		if (i+p[i]>R) 
		{
			pos=i;R=i+p[i];
		} 
	} 
		int MAX=0; 
		for (int i=1;i<=len;i++) 
			MAX=max(MAX,p[i]-1); 
		return MAX; 
	} 

字典序：

int trie[400001][26],pos,sum[400001];
void Insert(char *s) 
{
    int i = 0,c = 0;///c最初为根节点0
    while(s[i]) 
{
        int d = s[i] - 'a';
        if(!trie[c][d])        //如果为0表示没编号
            trie[c][d] = ++ pos;///编号从1开始
        c = trie[c][d];
        i ++;
    }
    sum[c] ++;
}

int Query(char *s) 
{
    int i = 0,c = 0;
    while(s[i]) 
    {
        int d = s[i] - 'a';
        if(!trie[c][d]) 
            return 0;
        c = trie[c][d];
        i ++;
    }
    return sum[c];
}