模板

模板总共分为两部分

• 插入一个字符串
• 查找一个字符串

int idx = 0;
int trie[3000010][150];
int ans[3000010];

##原理

trie==[上节点编号]==[下方连接的字母] = 下方连接的字母的节点编号

trie[0][0]=1;trie[0][1]=5;
trie[1][1]=2;
trie[2][1]=4;trie[2][2]=3;
trie[5][2]=6;
trie[6][0]=7;
其余trie[i][j]都为0，即空节点；
cnt[4]=cnt[3]=cnt[6]=cnt[7]=1;

void insert(string s)
{int p = 0;for (int i = 0; i < s.size(); i++){int x = s[i] - 'a';if (trie[p][x] == 0) trie[p][x] = ++id;p = trie[p][x];//cnt[p]++ //如果是寻找前缀和相同 在这里cnt[p]++}cnt[p]++;//如果是寻找完全相同 在这里cnt[p]++
}

int  find(string s)
{int p = 0;for (int i = 0; i < s.size(); i++){int x = s[i] - 'a';if (trie[p][x] == 0)return 0;p = trie[p][x];}return cnt[p];
}

例题

步骤

#include<iostream>
#define endl '\n'
using namespace std;
int idx = 0;
int trie[3000010][150];
int ans[3000010];
int trans(char s)
{if (s >= 'a' && s <= 'z'){return s - 'a' + 26;}if (s >= 'A' && s <= 'Z'){return s - 'A';}if (s >= '0' && s <= '9'){return s - '0' + 52;}}
void insert1(string s)
{int p = 0;for (int i = 0; s[i]; i++){int x = trans(s[i]);if (!trie[p][x]) trie[p][x] = ++idx;p = trie[p][x];ans[p]++;}
}
int find1(string k)
{int p = 0;for (int i = 0; k[i]; i++){int x =trans(k[i]);if (!trie[p][x]) return 0;p = trie[p][x];}return ans[p];
}int main()
{ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);int num;cin >> num;for (int i = 1; i <= num; i++){for (int x = 0; x <= idx; x++){for (int y = 0; y <= 122; y++){trie[x][y] = 0;}}for (int l = 0; l <= idx; l++){ans[l] = 0;}idx = 0;int n, m;cin >> n >> m;for (int j = 1; j <= n; j++){string s;cin >> s;insert1(s);}for (int k = 1; k <= m; k++){string s;cin >> s;cout<<find1(s)<<endl;}}return 0;
}