Updated tasks 1-22

Author: ThanhNIT

src/main/java/g0001_0100/s0001_two_sum/readme.md

@@ -97,4 +97,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Two Sum problem with a time complexity of O(n), where n is the number of elements in the input array.
+This implementation provides a solution to the Two Sum problem with a time complexity of O(n), where n is the number of elements in the input array.

src/main/java/g0001_0100/s0002_add_two_numbers/readme.md

@@ -130,4 +130,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Add Two Numbers problem using linked lists in Java.
+This implementation provides a solution to the Add Two Numbers problem using linked lists in Java.

src/main/java/g0001_0100/s0003_longest_substring_without_repeating_characters/readme.md

@@ -2,15 +2,15 @@
 
 Medium
 
-Given a string `s`, find the length of the **longest substring** without repeating characters.
+Given a string `s`, find the length of the **longest** **substring** without duplicate characters.
 
 **Example 1:**
 
 **Input:** s = "abcabcbb"
 
 **Output:** 3
 
-**Explanation:** The answer is "abc", with the length of 3. 
+**Explanation:** The answer is "abc", with the length of 3. Note that `"bca"` and `"cab"` are also correct answers. 
 
 **Example 2:**
 
@@ -28,12 +28,6 @@ Given a string `s`, find the length of the **longest substring** without repeati
 
 **Explanation:** The answer is "wke", with the length of 3. Notice that the answer must be a substring, "pwke" is a subsequence and not a substring. 
 
-**Example 4:**
-
-**Input:** s = ""
-
-**Output:** 0 
-
 **Constraints:**
 
 *   <code>0 <= s.length <= 5 * 10<sup>4</sup></code>
@@ -100,4 +94,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Longest Substring Without Repeating Characters problem in Java.
+This implementation provides a solution to the Longest Substring Without Repeating Characters problem in Java.

src/main/java/g0001_0100/s0004_median_of_two_sorted_arrays/readme.md

@@ -22,24 +22,6 @@ The overall run time complexity should be `O(log (m+n))`.
 
 **Explanation:** merged array = [1,2,3,4] and median is (2 + 3) / 2 = 2.5. 
 
-**Example 3:**
-
-**Input:** nums1 = [0,0], nums2 = [0,0]
-
-**Output:** 0.00000 
-
-**Example 4:**
-
-**Input:** nums1 = [], nums2 = [1]
-
-**Output:** 1.00000 
-
-**Example 5:**
-
-**Input:** nums1 = [2], nums2 = []
-
-**Output:** 2.00000 
-
 **Constraints:**
 
 *   `nums1.length == m`
@@ -115,4 +97,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Median of Two Sorted Arrays problem in Java with a runtime complexity of O(log(min(m, n))).
+This implementation provides a solution to the Median of Two Sorted Arrays problem in Java with a runtime complexity of O(log(min(m, n))).

src/main/java/g0001_0100/s0005_longest_palindromic_substring/readme.md

@@ -2,32 +2,22 @@
 
 Medium
 
-Given a string `s`, return _the longest palindromic substring_ in `s`.
+Given a string `s`, return _the longest_ _palindromic_ **substring** in `s`.
 
 **Example 1:**
 
 **Input:** s = "babad"
 
-**Output:** "bab" **Note:** "aba" is also a valid answer. 
+**Output:** "bab"
+
+**Explanation:** "aba" is also a valid answer. 
 
 **Example 2:**
 
 **Input:** s = "cbbd"
 
 **Output:** "bb" 
 
-**Example 3:**
-
-**Input:** s = "a"
-
-**Output:** "a" 
-
-**Example 4:**
-
-**Input:** s = "ac"
-
-**Output:** "a" 
-
 **Constraints:**
 
 *   `1 <= s.length <= 1000`
@@ -94,4 +84,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Longest Palindromic Substring problem in Java.
+This implementation provides a solution to the Longest Palindromic Substring problem in Java.

src/main/java/g0001_0100/s0006_zigzag_conversion/readme.md

@@ -104,4 +104,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Zigzag Conversion problem in Java.
+This implementation provides a solution to the Zigzag Conversion problem in Java.

src/main/java/g0001_0100/s0007_reverse_integer/readme.md

@@ -24,12 +24,6 @@ Given a signed 32-bit integer `x`, return `x` _with its digits reversed_. If rev
 
 **Output:** 21 
 
-**Example 4:**
-
-**Input:** x = 0
-
-**Output:** 0 
-
 **Constraints:**
 
 *   <code>-2<sup>31</sup> <= x <= 2<sup>31</sup> - 1</code>
@@ -93,4 +87,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Reverse Integer problem in Java.
+This implementation provides a solution to the Reverse Integer problem in Java.

src/main/java/g0001_0100/s0008_string_to_integer_atoi/readme.md

@@ -2,115 +2,87 @@
 
 Medium
 
-Implement the `myAtoi(string s)` function, which converts a string to a 32-bit signed integer (similar to C/C++'s `atoi` function).
+Implement the `myAtoi(string s)` function, which converts a string to a 32-bit signed integer.
 
 The algorithm for `myAtoi(string s)` is as follows:
 
-1.  Read in and ignore any leading whitespace.
-2.  Check if the next character (if not already at the end of the string) is `'-'` or `'+'`. Read this character in if it is either. This determines if the final result is negative or positive respectively. Assume the result is positive if neither is present.
-3.  Read in next the characters until the next non-digit character or the end of the input is reached. The rest of the string is ignored.
-4.  Convert these digits into an integer (i.e. `"123" -> 123`, `"0032" -> 32`). If no digits were read, then the integer is `0`. Change the sign as necessary (from step 2).
-5.  If the integer is out of the 32-bit signed integer range <code>[-2<sup>31</sup>, 2<sup>31</sup> - 1]</code>, then clamp the integer so that it remains in the range. Specifically, integers less than <code>-2<sup>31</sup></code> should be clamped to <code>-2<sup>31</sup></code>, and integers greater than <code>2<sup>31</sup> - 1</code> should be clamped to <code>2<sup>31</sup> - 1</code>.
-6.  Return the integer as the final result.
+1.  **Whitespace**: Ignore any leading whitespace (`" "`).
+2.  **Signedness**: Determine the sign by checking if the next character is `'-'` or `'+'`, assuming positivity if neither present.
+3.  **Conversion**: Read the integer by skipping leading zeros until a non-digit character is encountered or the end of the string is reached. If no digits were read, then the result is 0.
+4.  **Rounding**: If the integer is out of the 32-bit signed integer range <code>[-2<sup>31</sup>, 2<sup>31</sup> - 1]</code>, then round the integer to remain in the range. Specifically, integers less than <code>-2<sup>31</sup></code> should be rounded to <code>-2<sup>31</sup></code>, and integers greater than <code>2<sup>31</sup> - 1</code> should be rounded to <code>2<sup>31</sup> - 1</code>.
 
-**Note:**
-
-*   Only the space character `' '` is considered a whitespace character.
-*   **Do not ignore** any characters other than the leading whitespace or the rest of the string after the digits.
+Return the integer as the final result.
 
 **Example 1:**
 
 **Input:** s = "42"
 
 **Output:** 42
 
-**Explanation:** The underlined characters are what is read in, the caret is the current reader position.
+**Explanation:**
 
+    The underlined characters are what is read in and the caret is the current reader position.
     Step 1: "42" (no characters read because there is no leading whitespace)
-             ^ 
+             ^
     Step 2: "42" (no characters read because there is neither a '-' nor '+')
              ^
     Step 3: "42" ("42" is read in)
-               ^
-
-The parsed integer is 42. Since 42 is in the range [-2<sup>31</sup>, 2<sup>31</sup> - 1], the final result is 42. 
+              ^ 
 
 **Example 2:**
 
-**Input:** s = " -42"
+**Input:** s = " -042"
 
-**Output:** -42
+**Output:** \-42
 
 **Explanation:**
 
-    Step 1: " -42" (leading whitespace is read and ignored)
-              ^ 
-    Step 2: " -42" ('-' is read, so the result should be negative)
-               ^
-    Step 3: " -42" ("42" is read in)
-                 ^
-    The parsed integer is -42.
-
-Since -42 is in the range [-2<sup>31</sup>, 2<sup>31</sup> - 1], the final result is -42. 
+    Step 1: "___-042" (leading whitespace is read and ignored)
+                ^
+    Step 2: " -042" ('-' is read, so the result should be negative)
+              ^
+    Step 3: " -042" ("042" is read in, leading zeros ignored in the result)
+                 ^ 
 
 **Example 3:**
 
-**Input:** s = "4193 with words"
+**Input:** s = "1337c0d3"
 
-**Output:** 4193
+**Output:** 1337
 
 **Explanation:**
 
-    Step 1: "4193 with words" (no characters read because there is no leading whitespace)
+    Step 1: "1337c0d3" (no characters read because there is no leading whitespace)
              ^
-    Step 2: "4193 with words" (no characters read because there is neither a '-' nor '+')
+    Step 2: "1337c0d3" (no characters read because there is neither a '-' nor '+')
              ^
-    Step 3: "4193 with words" ("4193" is read in; reading stops because the next character is a non-digit)
+    Step 3: "1337c0d3" ("1337" is read in; reading stops because the next character is a non-digit)
                  ^ 
-    The parsed integer is 4193.
-
-Since 4193 is in the range [-2<sup>31</sup>, 2<sup>31</sup> - 1], the final result is 4193. 
 
 **Example 4:**
 
-**Input:** s = "words and 987"
+**Input:** s = "0-1"
 
 **Output:** 0
 
 **Explanation:**
 
-    Step 1: "words and 987" (no characters read because there is no leading whitespace)
+    Step 1: "0-1" (no characters read because there is no leading whitespace)
              ^
-    Step 2: "words and 987" (no characters read because there is neither a '-' nor '+')
+    Step 2: "0-1" (no characters read because there is neither a '-' nor '+')
              ^
-    Step 3: "words and 987" (reading stops immediately because there is a non-digit 'w')
-             ^
-    The parsed integer is 0 because no digits were read.
-
-Since 0 is in the range [-2<sup>31</sup>, 2<sup>31</sup> - 1], the final result is 0. 
+    Step 3: "0-1" ("0" is read in; reading stops because the next character is a non-digit)
+              ^ 
 
 **Example 5:**
 
-**Input:** s = "-91283472332"
+**Input:** s = "words and 987"
 
-**Output:** -2147483648
+**Output:** 0
 
 **Explanation:**
 
-    Step 1: "-91283472332" (no characters read because there is no leading whitespace)
-            ^
-    Step 2: "-91283472332" ('-' is read, so the result should be negative)
-              ^
-    Step 3: "-91283472332" ("91283472332" is read in)
-                         ^
-    The parsed integer is -91283472332.
-
-Since -91283472332 is less than the lower bound of the range [-2<sup>31</sup>, 2<sup>31</sup> - 1], the final result is clamped to -2<sup>31</sup> = -2147483648.  
-
-**Constraints:**
-
-*   `0 <= s.length <= 200`
-*   `s` consists of English letters (lower-case and upper-case), digits (`0-9`), `' '`, `'+'`, `'-'`, and `'.'`.
+Reading stops at the first non-digit character 'w'.
 
 To solve the String to Integer (atoi) problem in Java using a `Solution` class, we'll follow these steps:
 
@@ -181,4 +153,9 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the String to Integer (atoi) problem in Java.
+This implementation provides a solution to the String to Integer (atoi) problem in Java.
+
+**Constraints:**
+
+*   `0 <= s.length <= 200`
+*   `s` consists of English letters (lower-case and upper-case), digits (`0-9`), `' '`, `'+'`, `'-'`, and `'.'`.

src/main/java/g0001_0100/s0009_palindrome_number/readme.md

@@ -2,15 +2,15 @@
 
 Easy
 
-Given an integer `x`, return `true` if `x` is palindrome integer.
-
-An integer is a **palindrome** when it reads the same backward as forward. For example, `121` is palindrome while `123` is not.
+Given an integer `x`, return `true` _if_ `x` _is a_ _**palindrome**__, and_ `false` _otherwise_.
 
 **Example 1:**
 
 **Input:** x = 121
 
-**Output:** true 
+**Output:** true
+
+**Explanation:** 121 reads as 121 from left to right and from right to left. 
 
 **Example 2:**
 
@@ -28,12 +28,6 @@ An integer is a **palindrome** when it reads the same backward as forward. For e
 
 **Explanation:** Reads 01 from right to left. Therefore it is not a palindrome. 
 
-**Example 4:**
-
-**Input:** x = -101
-
-**Output:** false 
-
 **Constraints:**
 
 *   <code>-2<sup>31</sup> <= x <= 2<sup>31</sup> - 1</code>
@@ -97,4 +91,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Palindrome Number problem in Java.
+This implementation provides a solution to the Palindrome Number problem in Java.

src/main/java/g0001_0100/s0010_regular_expression_matching/readme.md

@@ -33,24 +33,10 @@ The matching should cover the **entire** input string (not partial).
 
 **Explanation:** ".\*" means "zero or more (\*) of any character (.)". 
 
-**Example 4:**
-
-**Input:** s = "aab", p = "c\*a\*b"
-
-**Output:** true
-
-**Explanation:** c can be repeated 0 times, a can be repeated 1 time. Therefore, it matches "aab". 
-
-**Example 5:**
-
-**Input:** s = "mississippi", p = "mis\*is\*p\*."
-
-**Output:** false 
-
 **Constraints:**
 
 *   `1 <= s.length <= 20`
-*   `1 <= p.length <= 30`
+*   `1 <= p.length <= 20`
 *   `s` contains only lowercase English letters.
 *   `p` contains only lowercase English letters, `'.'`, and `'*'`.
 *   It is guaranteed for each appearance of the character `'*'`, there will be a previous valid character to match.
@@ -116,4 +102,4 @@ public class Solution {
 }
 ```
 
-This implementation provides a solution to the Regular Expression Matching problem in Java.
+This implementation provides a solution to the Regular Expression Matching problem in Java.