hdu_1403_SAM_求最小公共前缀

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就是求最小公共前缀

#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>using namespace std;const int MAX_NODES = 3555555;const int N = 1111111;struct node{struct node *ch[26];struct node *f;int mx;void init(){memset(ch,0,sizeof(ch));f = 0;}}*root,*cnt,*tail,pool[MAX_NODES];char s[N],ts[N];int n;void insert(int c,int len){node *p = tail, *np = cnt++;for( ; p && !p->ch[c] ; p = p->f) p->ch[c] = np;np->mx = len;tail = np;if(!p) np->f = root;else if( p->ch[c]->mx == p->mx+1) np->f = p->ch[c];else{node *q = p->ch[c], *r = cnt++;*r = *q;r->mx = p->mx+1;q->f = np->f = r;for( ; p && p->ch[c] == q ; p = p->f) p->ch[c] = r; }}void init_suffix_auto(char s[]){int len = 0;tail = cnt = root = pool; cnt++ , root->init();for(int i = 0;i < (n<<1) ;i++)pool[i].init();for( ; s[len] ; len++){insert(s[len] - 'a', len+1);}}int main(){int t;while(scanf("%s",s)!=EOF){scanf("%s",ts);n = strlen(s);init_suffix_auto(s);node *p=root;int ans = 0,tmp=0;for(int i = 0; ts[i]; i++){int id = ts[i]-'a';if(p->ch[id]){p = p->ch[id];tmp++;}else{for(; p && !p->ch[id]; p = p->f) ;if(!p){p = root;tmp = 0;}else{tmp = p->mx+1;p = p->ch[id];}}ans = max(tmp,ans);}printf("%d\n",ans);}return 0;}

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