规范格式

leetcode/0720.Longest-Word-in-Dictionary/720. Longest Word in Dictionary.go

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+package leetcode
+
+import (
+	"sort"
+)
+
+func longestWord(words []string) string {
+	sort.Strings(words)
+	mp := make(map[string]bool)
+	var res string
+	for _, word := range words {
+		size := len(word)
+		if size == 1 || mp[word[:size-1]] {
+			if size > len(res) {
+				res = word
+			}
+			mp[word] = true
+		}
+	}
+	return res
+}

leetcode/0720.Longest-Word-in-Dictionary/720. Longest Word in Dictionary_test.go

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+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question720 struct {
+	para720
+	ans720
+}
+
+// para 是参数
+// one 代表第一个参数
+type para720 struct {
+	w []string
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans720 struct {
+	one string
+}
+
+func Test_Problem720(t *testing.T) {
+
+	qs := []question720{
+
+		question720{
+			para720{[]string{"w", "wo", "wor", "worl", "world"}},
+			ans720{"world"},
+		},
+
+		question720{
+			para720{[]string{"a", "banana", "app", "appl", "ap", "apply", "apple"}},
+			ans720{"apple"},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 720------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans720, q.para720
+		fmt.Printf("【input】:%v       【output】:%v\n", p, longestWord(p.w))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/0720.Longest-Word-in-Dictionary/README.md

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+# [720. Longest Word in Dictionary](https://leetcode.com/problems/longest-word-in-dictionary/)
+
+
+## 题目
+
+Given a list of strings `words` representing an English Dictionary, find the longest word in `words` that can be built one character at a time by other words in `words`. If there is more than one possible answer, return the longest word with the smallest lexicographical order.
+
+If there is no answer, return the empty string.
+
+**Example 1:**
+
+    Input: 
+    words = ["w","wo","wor","worl", "world"]
+    Output: "world"
+    Explanation: 
+    The word "world" can be built one character at a time by "w", "wo", "wor", and "worl".
+
+**Example 2:**
+
+    Input: 
+    words = ["a", "banana", "app", "appl", "ap", "apply", "apple"]
+    Output: "apple"
+    Explanation: 
+    Both "apply" and "apple" can be built from other words in the dictionary. However, "apple" is lexicographically smaller than "apply".
+
+**Note:**
+
+- All the strings in the input will only contain lowercase letters.
+- The length of `words` will be in the range `[1, 1000]`.
+- The length of `words[i]` will be in the range `[1, 30]`.
+
+
+## 题目大意
+
+给出一个字符串数组 words 组成的一本英语词典。从中找出最长的一个单词，该单词是由 words 词典中其他单词逐步添加一个字母组成。若其中有多个可行的答案，则返回答案中字典序最小的单词。若无答案，则返回空字符串。
+
+
+
+## 解题思路
+
+
+- 给出一个字符串数组，要求找到长度最长的，并且可以由字符串数组里面其他字符串拼接一个字符组成的字符串。如果存在多个这样的最长的字符串，则输出字典序较小的那个字符串，如果找不到这样的字符串，输出空字符串。
+- 这道题解题思路是先排序，排序完成以后就是字典序从小到大了。之后再用 map 辅助记录即可。