added problem 2000

Author: SHA65536

Diff for: problems/problem2000/reverse_prefix_of_word.go

@@ -0,0 +1,26 @@
+package problem2000
+
+import "strings"
+
+/*
+Given a 0-indexed string word and a character ch,
+reverse the segment of word that starts at index 0 and ends at the index of the first occurrence of ch (inclusive).
+If the character ch does not exist in word, do nothing.
+For example, if word = "abcdefd" and ch = "d", then you should reverse the segment that starts at 0 and ends at 3 (inclusive).
+The resulting string will be "dcbaefd".
+Return the resulting string.
+*/
+
+func reversePrefix(word string, ch byte) string {
+	var end int = strings.IndexByte(word, ch)
+	var data []byte
+	if end == -1 {
+		return word
+	}
+	data = []byte(word)
+	for i := 0; end > i; i++ {
+		data[i], data[end] = data[end], data[i]
+		end--
+	}
+	return string(data)
+}

Diff for: problems/problem2000/reverse_prefix_of_word_test.go

@@ -0,0 +1,30 @@
+package problem2000
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type Result struct {
+	Input    string
+	Char     byte
+	Expected string
+}
+
+var Results = []Result{
+	{"abcdefd", 'd', "dcbaefd"},
+	{"xyxzxe", 'z', "zxyxxe"},
+	{"abcd", 'z', "abcd"},
+}
+
+func TestReversePrefix(t *testing.T) {
+	assert := assert.New(t)
+
+	for _, res := range Results {
+		want := res.Expected
+		got := reversePrefix(res.Input, res.Char)
+		assert.Equal(want, got, fmt.Sprintf("%+v", res))
+	}
+}

Diff for: readme.md

@@ -270,6 +270,7 @@ Each problem is in it's own directory, with test files. There are helper package
 | 1844 | [Replace All Digits with Characters](https://leetcode.com/problems/replace-all-digits-with-characters) | [My Solution](./problems/problem1844) | ✅ |
 | 1926 | [Nearest Exit from Entrance in Maze](https://leetcode.com/problems/nearest-exit-from-entrance-in-maze) | [My Solution](./problems/problem1926) | ✅ |
 | 1996 | [The Number of Weak Characters in the Game](https://leetcode.com/problems/the-number-of-weak-characters-in-the-game) | [My Solution](./problems/problem1996) | ✅ |
+| 2000 | [Reverse Prefix of Word](https://leetcode.com/problems/reverse-prefix-of-word/) | [My Solution](./problems/problem2000) | ✅ |
 | 2007 | [Find Original Array From Doubled Array](https://leetcode.com/problems/find-original-array-from-doubled-array) | [My Solution](./problems/problem2007) | ✅ |
 | 2095 | [Delete the Middle Node of a Linked List](https://leetcode.com/problems/delete-the-middle-node-of-a-linked-list) | [My Solution](./problems/problem2095) | ✅ |
 | 2131 | [Longest Palindrome by Concatenating Two Letter Words](https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words) | [My Solution](./problems/problem2131) | ✅ |