标签：struct == tar div solution this logs void const
Given a 2D board and a list of words from the dictionary, find all words in the board.
Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once in a word.
For example,
Given words = ["oath","pea","eat","rain"] and board =
[
[‘o‘,‘a‘,‘a‘,‘n‘],
[‘e‘,‘t‘,‘a‘,‘e‘],
[‘i‘,‘h‘,‘k‘,‘r‘],
[‘i‘,‘f‘,‘l‘,‘v‘]
]
Return ["eat","oath"].
Note:
You may assume that all inputs are consist of lowercase letters a-z.
好慢啊:１５％ 如何优化！
public class Solution {
public class TrieNode {
int count;
TrieNode[] children = new TrieNode[26];
public void insert(String word) {
TrieNode cur = this;
int i = 0;
while (i < word.length()) {
if (cur.children[word.charAt(i) - ‘a‘] == null) {
cur.children[word.charAt(i) - ‘a‘] = new TrieNode();
}
cur = cur.children[word.charAt(i) - ‘a‘];
i++;
}
cur.count = 1;
}
// 0: not prefix, 1: prefix, 2: contains string
public int startsWith(String prefix) {
TrieNode cur = this;
int i = 0;
while (i < prefix.length()) {
if (cur.children[prefix.charAt(i) - ‘a‘] == null) {
return 0;
}
cur = cur.children[prefix.charAt(i) - ‘a‘];
i++;
}
if (cur.count == 0) {
return 1;
} else {
cur.count = 0;
return 2;
}
}
}
TrieNode root = new TrieNode();
public List<String> findWords(char[][] board, String[] words) {
for (int i = 0; i < words.length; i++) {
root.insert(words[i]);
}
boolean[][] visited = new boolean[board.length][board[0].length];
List<String> re = new LinkedList<String>();
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board[0].length; j++) {
find(board, visited, i, j, "", re);
}
}
return re;
}
public void find(char[][] board, boolean[][] visited, int i, int j, String str, List<String> list) {
if (i < 0 || i > board.length - 1 || j < 0 || j > board[0].length - 1 || visited[i][j]) {
return;
}
String tmp = str + board[i][j];
int starts = root.startsWith(tmp);
if (starts == 0) {
return;
} else {
if (starts == 2) {
list.add(tmp);
}
visited[i][j] = true;
find(board, visited, i - 1, j, tmp, list);
find(board, visited, i + 1, j, tmp, list);
find(board, visited, i, j - 1, tmp, list);
find(board, visited, i, j + 1, tmp, list);
visited[i][j] = false;
}
}
}
标签：struct == tar div solution this logs void const
原文地址：http://www.cnblogs.com/yuchenkit/p/7223491.html
