docs: add number 27 and 28

Author: bujosa

README.md

@@ -13,6 +13,8 @@ In this project, I will try to solve leetcode challenges in rust.
   - [x] [13. Roman to interger](src/easy/roman_to_integer.rs)
   - [x] [14. Longest common prefix](src/easy/longest_common_prefix.rs)
   - [x] [21. Merge two sorted lists](src/easy/merge_two_sorted_lists.rs)
+  - [x] [27. Remove element](src/easy/remove_element.rs)
+  - [x] [28. Implement strStr()](src/easy/implement_strstr.rs)
   - [x] [234. Palindrome linked list](src/easy/palindrome_linked_list.rs)
 
 

src/easy/find_the_index_of_the_first_occurrence_in_a_string.rs renamed to src/easy/implement_strstr.rs

@@ -1,4 +1,4 @@
-pub mod find_the_index_of_the_first_occurrence_in_a_string;
+pub mod implement_strstr;
 pub mod longest_common_prefix;
 pub mod merged_two_sorted_lists;
 pub mod palindrome_linked_list;

src/easy/mod.rs

@@ -203,6 +203,33 @@ Put the code below in main.rs and run `cargo run`
   println!("result: {:?}", result);
 ```
 
+# 28. Implement strStr()
+
+## Description
+
+Given a haystack string and a needle string, find the first occurrence of needle in haystack. If no needle is found, return -1.
+
+## Examples
+```text
+Input: haystack = "hello", needle = "ll"
+Output: 2
+
+Input: haystack = "aaaaa", needle = "bba"
+Output: -1
+```
+
+## How to Run in main.rs
+
+Put the code below in main.rs and run `cargo run`
+
+```rust
+  let haystack = String::from("hello");
+  let needle = String::from("ll");
+  let result = easy::implement_strstr::str_str(haystack, needle);
+  println!("result: {:?}", result);
+```
+
+
 
 # 234. Palindrome linked list