HDU4622：区间查询不同子串个数
用后缀自动机预处理出所有区间的不同子串个数
建立n次后缀自动机
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 #include <iostream> 5 using namespace std; 6 7 const int CHAR = 26; 8 const int MAXN = 2020; 9 struct SAM_Node 10 { 11 SAM_Node *fa,*next[CHAR]; 12 int len; 13 int id,pos; 14 SAM_Node(){} 15 SAM_Node(int _len) 16 { 17 fa = 0; 18 len = _len; 19 memset(next,0,sizeof(next)); 20 } 21 }; 22 SAM_Node SAM_node[MAXN*2], *SAM_root, *SAM_last; 23 int SAM_size; 24 SAM_Node *newSAM_Node(int len) 25 { 26 SAM_node[SAM_size] = SAM_Node(len); 27 SAM_node[SAM_size].id = SAM_size; 28 return &SAM_node[SAM_size++]; 29 } 30 SAM_Node *newSAM_Node(SAM_Node *p) 31 { 32 SAM_node[SAM_size] = *p; 33 SAM_node[SAM_size].id = SAM_size; 34 return &SAM_node[SAM_size++]; 35 } 36 void SAM_init() 37 { 38 SAM_size = 0; 39 SAM_root = SAM_last = newSAM_Node(0); 40 SAM_node[0].pos = 0; 41 } 42 void SAM_add(int x,int len) 43 { 44 SAM_Node *p = SAM_last, *np = newSAM_Node(p->len+1); 45 np->pos = len; 46 SAM_last = np; 47 for(;p && !p->next[x];p = p->fa) 48 p->next[x] = np; 49 if(!p) 50 { 51 np->fa = SAM_root; 52 return; 53 } 54 SAM_Node *q = p->next[x]; 55 if(q->len == p->len + 1) 56 { 57 np->fa = q; 58 return; 59 } 60 SAM_Node *nq = newSAM_Node(q); 61 nq->len = p->len + 1; 62 q->fa = nq; 63 np->fa = nq; 64 for(;p && p->next[x] == q;p = p->fa) 65 p->next[x] = nq; 66 } 67 void SAM_build(char *s) 68 { 69 SAM_init(); 70 int len = strlen(s); 71 for(int i = 0;i < len;i++) 72 SAM_add(s[i] - 'a',i+1); 73 } 74 75 int Q[MAXN][MAXN]; 76 char str[MAXN]; 77 int main() 78 { 79 int T; 80 scanf("%d",&T); 81 while(T--) 82 { 83 scanf("%s",str); 84 int n = strlen(str); 85 memset(Q,0,sizeof(Q)); 86 for(int i = 0;i < n;i++) 87 { 88 SAM_init(); 89 for(int j = i;j < n;j++) 90 { 91 SAM_add(str[j]-'a',j-i+1); 92 } 93 for(int j = 1;j < SAM_size;j++) 94 { 95 Q[i][SAM_node[j].pos-1+i]+=SAM_node[j].len - SAM_node[j].fa->len; 96 } 97 for(int j = i+1;j < n;j++) 98 Q[i][j] += Q[i][j-1]; 99 } 100 int M; 101 int u,v; 102 scanf("%d",&M); 103 while(M--) 104 { 105 scanf("%d%d",&u,&v); 106 u--;v--; 107 printf("%d ",Q[u][v]); 108 } 109 } 110 return 0; 111 }
此题也有字符串哈希做法
没看懂就不贴了