add: leetcode 0058 solution

leetcode/0058.Length-of-Last-Word/58.Length of Last Word.go

@@ -0,0 +1,16 @@
+package leetcode
+
+func lengthOfLastWord(s string) int {
+	last := len(s) - 1
+	for last >= 0 && s[last] == ' ' {
+		last--
+	}
+	if last < 0 {
+		return 0
+	}
+	first := last
+	for first >= 0 && s[first] != ' ' {
+		first--
+	}
+	return last - first
+}

leetcode/0058.Length-of-Last-Word/58.Length of Last Word_test.go

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+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question58 struct {
+	para58
+	ans58
+}
+
+// para 是参数
+type para58 struct {
+	s string
+}
+
+// ans 是答案
+type ans58 struct {
+	ans int
+}
+
+func Test_Problem58(t *testing.T) {
+
+	qs := []question58{
+
+		{
+			para58{"Hello World"},
+			ans58{5},
+		},
+
+		{
+			para58{"   fly me   to   the moon  "},
+			ans58{4},
+		},
+
+		{
+			para58{"luffy is still joyboy"},
+			ans58{6},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 58------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans58, q.para58
+		fmt.Printf("【input】:%v       【output】:%v\n", p, lengthOfLastWord(p.s))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/0058.Length-of-Last-Word/README.md

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+# [58. Length of Last Word](https://leetcode-cn.com/problems/length-of-last-word/)
+
+## 题目
+
+Given a string s consisting of some words separated by some number of spaces, return the length of the last word in the string.
+
+A word is a maximal substring consisting of non-space characters only.
+
+Example 1:
+
+```
+Input: s = "Hello World"
+Output: 5
+Explanation: The last word is "World" with length 5.
+```
+
+Example 2:
+
+```
+Input: s = "   fly me   to   the moon  "
+Output: 4
+Explanation: The last word is "moon" with length 4.
+```
+
+Example 3:
+
+```
+Input: s = "luffy is still joyboy"
+Output: 6
+Explanation: The last word is "joyboy" with length 6.
+```
+
+## 题目大意
+
+给你一个字符串 s，由若干单词组成，单词前后用一些空格字符隔开。返回字符串中最后一个单词的长度。
+
+单词 是指仅由字母组成、不包含任何空格字符的最大子字符串。
+
+## 解题思路
+
+- 先从后过滤掉空格找到单词尾部，再从尾部向前遍历，找到单词头部，最后两者相减，即为单词的长度