Merge pull request #209 from gostool/leetcode1816

Leetcode1816

leetcode/1816.Truncate-Sentence/1816.Truncate Sentence.go

@@ -0,0 +1,18 @@
+package leetcode
+
+func truncateSentence(s string, k int) string {
+	end := 0
+	for i := range s {
+		if k > 0 && s[i] == ' ' {
+			k--
+		}
+		if k == 0 {
+			end = i
+			break
+		}
+	}
+	if end == 0 {
+		return s
+	}
+	return s[:end]
+}

leetcode/1816.Truncate-Sentence/1816.Truncate Sentence_test.go

@@ -0,0 +1,51 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question1816 struct {
+	para1816
+	ans1816
+}
+
+// para 是参数
+type para1816 struct {
+	s string
+	k int
+}
+
+// ans 是答案
+type ans1816 struct {
+	ans string
+}
+
+func Test_Problem1816(t *testing.T) {
+
+	qs := []question1816{
+
+		{
+			para1816{"Hello how are you Contestant", 4},
+			ans1816{"Hello how are you"},
+		},
+
+		{
+			para1816{"What is the solution to this problem", 4},
+			ans1816{"What is the solution"},
+		},
+
+		{
+			para1816{"chopper is not a tanuki", 5},
+			ans1816{"chopper is not a tanuki"},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 1816------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans1816, q.para1816
+		fmt.Printf("【input】:%v    【output】:%v\n", p, truncateSentence(p.s, p.k))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/1816.Truncate-Sentence/README.md

@@ -0,0 +1,76 @@
+# [1816. Truncate Sentence](https://leetcode-cn.com/problems/truncate-sentence/)
+
+## 题目
+
+A sentence is a list of words that are separated by a single space with no leading or trailing spaces. Each of the words consists of only uppercase and lowercase English letters (no punctuation).
+
+- For example, "Hello World", "HELLO", and "hello world hello world" are all sentences.
+
+You are given a sentence s and an integer k. You want to truncate s such that it contains only the first k words. Return s after truncating it.
+
+**Example 1**:
+
+    Input: s = "Hello how are you Contestant", k = 4
+    Output: "Hello how are you"
+    Explanation:
+    The words in s are ["Hello", "how" "are", "you", "Contestant"].
+    The first 4 words are ["Hello", "how", "are", "you"].
+    Hence, you should return "Hello how are you".
+
+**Example 2**:
+
+    Input: s = "What is the solution to this problem", k = 4
+    Output: "What is the solution"
+    Explanation:
+    The words in s are ["What", "is" "the", "solution", "to", "this", "problem"].
+    The first 4 words are ["What", "is", "the", "solution"].
+    Hence, you should return "What is the solution".
+
+**Example 3**:
+
+    Input: s = "chopper is not a tanuki", k = 5
+    Output: "chopper is not a tanuki"
+
+**Constraints:**
+
+- 1 <= s.length <= 500
+- k is in the range [1, the number of words in s].
+- s consist of only lowercase and uppercase English letters and spaces.
+- The words in s are separated by a single space.
+- There are no leading or trailing spaces.
+
+## 题目大意
+
+句子 是一个单词列表，列表中的单词之间用单个空格隔开，且不存在前导或尾随空格。每个单词仅由大小写英文字母组成（不含标点符号）。
+
+- 例如，"Hello World"、"HELLO" 和 "hello world hello world" 都是句子。
+
+给你一个句子 s 和一个整数 k ，请你将 s 截断使截断后的句子仅含前 k 个单词。返回截断 s 后得到的句子。
+
+## 解题思路
+
+- 遍历字符串s，找到最后一个空格的下标end
+- 如果end为0，直接返回s,否则返回s[:end]
+
+## 代码
+
+```go
+package leetcode
+
+func truncateSentence(s string, k int) string {
+	end := 0
+	for i := range s {
+		if k > 0 && s[i] == ' ' {
+			k--
+		}
+		if k == 0 {
+			end = i
+			break
+		}
+	}
+	if end == 0 {
+		return s
+	}
+	return s[:end]
+}
+```