洛谷P2237 [USACO14FEB]自动完成Auto-complete

Posted 2020-10-24 third2333

 

洛谷P2237 [USACO14FEB]自动完成Auto-complete
Trie树

 

 1 #include <bits/stdc++.h>
 2 #define For(i, j, k) for(int i=j; i<=k; i++)
 3 #define Dow(i, j, k) for(int i=j; i>=k; i--)
 4 #define LL long long
 5 using namespace std;
 6 inline int read() {
 7     int x = 0, f = 1;
 8     char ch = getchar();
 9     while(ch<‘0‘||ch>‘9‘) { if(ch==‘-‘) f = -1; ch = getchar(); }
10     while(ch>=‘0‘&&ch<=‘9‘) { x = x*10+ch-48; ch = getchar(); }
11     return x * f;
12 }
13 void write(int x) {
14     if(x<0) putchar(‘-‘), x=-x;
15     if(x>9) write(x/10);
16     putchar(x%10+48);
17 }
18 void writeln(int x) { write(x); puts(""); }
19 
20 const int N = 1000011; 
21 int n, tot, K, Q; 
22 int son[N][26], siz[N], to[N]; 
23 char ch[N]; 
24 
25 inline void insert(int id, char ch[]) {
26     int now = 0; 
27     int len = strlen(ch+1); 
28     For(i, 1, len) {
29         if(!son[now][ch[i]-‘a‘]) son[now][ch[i]-‘a‘] = ++tot; 
30         now = son[now][ch[i]-‘a‘]; ++siz[now]; 
31     }
32     to[now] = id; 
33 }
34 
35 inline int Query(int K, char ch[]) {
36     int now = 0; 
37     int len = strlen(ch+1); 
38     For(i, 1, len) {
39         if(!son[now][ch[i]-‘a‘]) return -1; 
40         now = son[now][ch[i]-‘a‘]; 
41     }
42     if(siz[now] < K) return -1; 
43     while(1) {
44         if(to[now] && K==1) return to[now]; 
45         if(to[now]) --K; 
46         For(i, 0, 25) 
47             if(siz[son[now][i]] < K) 
48                 K -= siz[son[now][i]]; 
49             else {
50                 now = son[now][i]; 
51                 break; 
52             }
53     }
54 }
55 
56 int main() {
57     n = read(); Q = read(); 
58     For(i, 1, n) {
59         scanf("%s", ch+1); 
60         insert(i, ch); 
61     }
62     while(Q--) {
63         K = read(); 
64         scanf("%s", ch+1); 
65         writeln(Query(K, ch));
66     }
67     return 0; 
68 }