title
单词数组 words 的 有效编码 由任意助记字符串 s 和下标数组 indices 组成,且满足:
words.length == indices.length- 助记字符串
s以'#'字符结尾 - 对于每个下标
indices[i],s的一个从indices[i]开始、到下一个'#'字符结束(但不包括'#')的 子字符串 恰好与words[i]相等
给你一个单词数组 words ,返回成功对 words 进行编码的最小助记字符串 s 的长度 。
示例 1:
输入:words = ["time", "me", "bell"]
输出:10
解释:一组有效编码为 s = "time#bell#" 和 indices = [0, 2, 5] 。
words[0] = "time" ,s 开始于 indices[0] = 0 到下一个 '#' 结束的子字符串,如加粗部分所示 "time#bell#"
words[1] = "me" ,s 开始于 indices[1] = 2 到下一个 '#' 结束的子字符串,如加粗部分所示 "time#bell#"
words[2] = "bell" ,s 开始于 indices[2] = 5 到下一个 '#' 结束的子字符串,如加粗部分所示 "time#bell#"
示例 2:
输入:words = ["t"]
输出:2
解释:一组有效编码为 s = "t#" 和 indices = [0] 。
提示:
1 <= words.length <= 20001 <= words[i].length <= 7words[i]仅由小写字母组成
solution
https://github.com/azl397985856/leetcode/blob/master/problems/820.short-encoding-of-words.md
class TrieNode:
def __init__(self):
self.count = 0
self.children = {}
class Solution:
def minimumLengthEncoding(self, words: List[str]) -> int:
trie = TrieNode()
for word in words:
node = trie
for c in reversed(word):
if c not in node.children:
node.children[c] = TrieNode()
node = node.children[c]
node.count += 1
def searchIsLeaf(word):
node = trie
for c in word:
if c not in node.children:
return False
node = node.children[c]
# 这是关键,判断它是否是叶子节点
return len(node.children) == 0
# visit = []
#
# def dfs(node, cur):
# if not node.children:
# visit.append(cur)
# return
# for _, child in node.children.items():
# dfs(child, cur + 1)
#
# dfs(trie, 0)
# return len(visit) + sum(visit)
ans = 0
for word in words:
if searchIsLeaf(word[::-1]):
ans += len(word) + 1
return ans