HDU 1251 統計難題 （java版字典樹）

十分基礎的字典樹，直接上代碼

import java.io.BufferedInputStream;import java.util.Scanner;public class Main {private static Scanner cin = new Scanner(new BufferedInputStream(System.in));public static void main(String[] args) {Trie root = new Trie();String str;boolean flag = true;while(flag) {str = cin.nextLine();if("".equals(str)){flag = false;}insert(root, str);}while(cin.hasNext()){str = cin.nextLine();System.out.println( search(root, str) );}}private static void insert(final Trie root, String str){Trie cur = root;int idx;for(int i = 0; i < str.length(); i++){idx = str.charAt(i) - 'a';if(cur.child[idx] == null){cur.child[idx] = new Trie();}cur = cur.child[idx];cur.ch = str.charAt(i);cur.cnt = cur.cnt + 1;}}private static int search(final Trie root, String str){int cnt = 0;Trie cur = root;int idx;for(int i = 0; i < str.length(); i++) {idx = str.charAt(i) - 'a';if(cur.child[idx] == null){return 0;}cur = cur.child[idx];cnt = cur.cnt;}return cnt;}}class Trie {char ch;int cnt;Trie[] child;public Trie() {cnt = 0;child = new Trie[26];}}