Trie 字典树

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 #include<iostream>
 5 #include<vector>
 6 using namespace std;
 7 const int MOD = 20071027;
 8 struct Trie
 9 {
10     int word[4001 * 100][26];
11     int ex[4001 * 100];
12     int size;
13 
14     void clear()
15     {
16         memset(word[0], 0, sizeof(word[0]));
17         size = 1;
18         ex[0] = 0;
19     }
20 
21     void insert(char *s, int v)
22     {
23         int Now = 0, curchr;
24         for (int i = 0; s[i] != ‘\0‘; i++)
25         {
26             int c = s[i] - ‘a‘;
27             if (!word[Now][c])
28             {
29                 memset(word[size], 0, sizeof(word[size]));
30                 ex[size] = 0;
31                 word[Now][c] = size++;
32             }
33             Now = word[Now][c];
34         }
35         ex[Now] = v;
36     }
37 
38     int search(char *s, int len, vector<int>& ans)
39     {
40         int u = 0, c;
41         for (int i = 0; s[i] != ‘\0‘&&i<len; i++)
42         {
43             c = s[i] - ‘a‘;
44             if (!word[u][c])return 0;
45             u = word[u][c];
46             if (ex[u])
47                 ans.push_back(ex[u]);
48         }
49     }
50 } tree;
51 
52 char s[300001];
53 char tmp[101];
54 int dp[300001];
55 int n;
56 int ll[4001];//记录每个字符串的长度
57 int main()
58 {
59     int Case = 1;
60     while (~scanf("%s",s))
61     {
62         scanf("%d", &n);
63         tree.clear();
64         memset(dp, 0, sizeof(dp));
65         int len = strlen(s);
66 
67         for (int i = 0; i<n; i++)
68         {
69             scanf("%s", tmp);
70             ll[i + 1] = strlen(tmp);
71             tree.insert(tmp, i + 1);
72         }
73         dp[len] = 1;
74         for (int i = len - 1; i >= 0; i--)
75         {//找下标为i~len-1的子字符串的前缀字符串
76             vector<int>ans;
77             tree.search(s + i, len - i, ans);
78             for (int j = 0; j<ans.size(); j++)
79                 dp[i] = (dp[i] + dp[i + ll[ans[j]]]) % MOD;
80         }
81         printf("Case %d: %d\n", Case++, dp[0]);
82     }
83     return 0;
84 }

 1 #include <cstdio>
 2 #include <cstring>
 3 #define MAXN 4001010
 4 #define ll long long
 5 using namespace std;
 6 //左儿子右兄弟表示字典树
 7 int head[MAXN];// head[i]为第i个结点的左儿子编号
 8 int next[MAXN];// next[i]为第i个结点的右兄弟编号
 9 int tot[MAXN];// tot[i]为第i个结点为根的子树包含的叶结点(即以包含其的前缀的字符串个数)总数
10 int ed[MAXN];// ed[i]为第i个结点结束的字符串的个数
11 char ch[MAXN];// ch[i]为第i个结点上的字符
12 int sz;
13 ll sum;
14 void init()
15 {// 初始时只有一个根结点
16     sz = 1; head[0] = next[0] = tot[0] = 0; sum = 0;
17 }
18 
19 void insert(char *s)
20 {
21     int u, v, n = strlen(s);
22     u = 0;
23     for (int i = 0; i<n; i++)
24     {
25         bool f = 0;
26         for (v = head[u]; v != 0; v = next[v])
27         {//找字符s[i]
28             if (ch[v] == s[i])
29             {
30                 f = 1; break;
31             }
32         }
33         if (!f)
34         {//如果没找到，新建结点
35             v = sz++;
36             tot[v] = 0;
37             ed[v] = 0;
38             ch[v] = s[i];
39             next[v] = head[u];//插入首部
40             head[u] = v;
41             head[v] = 0;
42         }
43         u = v;
44         sum += tot[v] * 2;
45         tot[v]++;
46     }
47     sum += ed[u];
48     ed[u]++;
49 }
50 int main()
51 {
52     int n;
53     char s[1002];
54     int Case = 1;
55     while(~scanf("%d", &n)&&n)
56     {
57         init();
58         for (int i = 0; i<n; i++)
59         {
60             scanf("%s", s);
61             insert(s);
62         }
63         printf("Case %d: %lld\n", Case++, sum + n*(n - 1) / 2);
64     }
65     return 0;
66 }

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstring>
 4 using namespace std;
 5 
 6 const int maxn = 10000010;
 7 const int Char_size = 2;
 8 struct Trie
 9 {
10     int word[maxn][Char_size];//结点
11     int val[maxn];//附加信息
12     int size;//总结点数
13     int ans;
14 
15     void Init()
16     {
17         memset(word[0], 0, sizeof(word[0]));
18         size = 1;
19         val[0] = 0;
20         ans = 0;
21     }
22     int getID(char c)
23     {
24         return c - ‘0‘;
25     }
26     void Insert(char *s)
27     {
28         int now = 0, curchr;
29         for (int i = 0; s[i] != ‘\0‘; i++)
30         {
31             int pos =getID(s[i]);
32             if (!word[now][pos])
33             {
34                 memset(word[size], 0, sizeof(word[size]));
35                 val[size] = 0;
36                 word[now][pos] = size++;
37             }
38             now = word[now][pos];
39             val[now] += i + 1;//累加到该结点的前缀的长度
40             ans = max(ans, val[now]);
41         }
42     }
43 }tree;
44 
45 char str[maxn];
46 int main()
47 {
48     int t;
49     scanf("%d", &t);
50     while (t--)
51     {
52         tree.Init();
53         int n;
54         scanf("%d", &n);
55         while (n--)
56         {
57             scanf("%s", str);
58             tree.Insert(str);
59         }
60         printf("%d\n", tree.ans);
61     }
62     return 0;
63 }