Update solution 0003

leetcode/0003.Longest-Substring-Without-Repeating-Characters/3. Longest Substring Without Repeating Characters.go

@@ -8,7 +8,7 @@ func lengthOfLongestSubstring(s string) int {
 	var bitSet [256]bool
 	result, left, right := 0, 0, 0
 	for left < len(s) {
-		// 右侧字符对应的bitSet被标记true，说明此字符在X位置重复，需要左侧向前移动，直到将X标记为false
+		// 右侧字符对应的 bitSet 被标记 true，说明此字符在 X 位置重复，需要左侧向前移动，直到将 X 标记为 false
 		if bitSet[s[right]] {
 			bitSet[s[left]] = false
 			left++
@@ -26,23 +26,28 @@ func lengthOfLongestSubstring(s string) int {
 	return result
 }
 
-// 解法二 滑动窗口-数组桶
+// 解法二 滑动窗口
 func lengthOfLongestSubstring1(s string) int {
-	right, left, res := 0, 0, 0
-	var indexes [256]int
-	for left < len(s) {
-		tmp := indexes[s[left]-'a']
-		if tmp >= right {
-			right = tmp + 1
-		}
-		indexes[s[left]-'a'] = left
-		left++
-		res = max(res, left-right)
+	if len(s) == 0 {
+		return 0
 	}
-	return res
+	var freq [256]int
+	result, left, right := 0, 0, -1
+
+	for left < len(s) {
+		if right+1 < len(s) && freq[s[right+1]-'a'] == 0 {
+			freq[s[right+1]-'a']++
+			right++
+		} else {
+			freq[s[left]-'a']--
+			left++
+		}
+		result = max(result, right-left+1)
+	}
+	return result
 }
 
-// 解法二 滑动窗口-哈希桶
+// 解法三 滑动窗口-哈希桶
 func lengthOfLongestSubstring2(s string) int {
 	right, left, res := 0, 0, 0
 	indexes := make(map[byte]int, len(s))

leetcode/0003.Longest-Substring-Without-Repeating-Characters/3. Longest Substring Without Repeating Characters_test.go

@@ -51,7 +51,7 @@ func Test_Problem3(t *testing.T) {
 
 	for _, q := range qs {
 		_, p := q.ans3, q.para3
-		fmt.Printf("【input】:%v       【output】:%v\n", p, lengthOfLongestSubstring_(p.s))
+		fmt.Printf("【input】:%v       【output】:%v\n", p, lengthOfLongestSubstring(p.s))
 	}
 	fmt.Printf("\n\n\n")
 }