feat(strings, trie): is prefix of word

This adds a function `is_prefix_of_word` that enables searching for the
index of a `search_word` in a given sentence and return the index if it
exists. The index is 1-based.

This modifies the `TrieNode` allowing callers to use the `TrieNode` to
build a trie from the node and perform prefix searches a well as
modifies the `Trie` class as well adding modifications and optimizations
that match the changes in the `TrieNode` class.

Also note that this change includes an `index` to the `TrieNode` to
track the earliest index of a given character in a sentence. That is,
what is the earliest that a word has been seen, This allows returning
multiple words in the case of using the `Trie` `search` functionality.

Author: BrianLusina

algorithms/fast_and_slow/happy_number/README.md

@@ -15,26 +15,26 @@ Return TRUE if n is a happy number, and FALSE if not.
 
 ### Sample Example 1
 
-![Sample Example 1.1](example_1_1.png)
-![Sample Example 1.2](example_1_2.png)
-![Sample Example 1.3](example_1_3.png)
+![Sample Example 1.1](images/example/example_1_1.png)
+![Sample Example 1.2](images/example/example_1_2.png)
+![Sample Example 1.3](images/example/example_1_3.png)
 
 ### Sample Example 2
 
-![Sample Example 2.1](example_2_1.png)
-![Sample Example 2.2](example_2_2.png)
-![Sample Example 2.3](example_2_3.png)
+![Sample Example 2.1](images/example/example_2_1.png)
+![Sample Example 2.2](images/example/example_2_2.png)
+![Sample Example 2.3](images/example/example_2_3.png)
 
 ## Solution Example
 
 Below shows an example using Floyd's Cycle Detection Algorithm or Tortoise and Hare algorithm to detect a cycle
 for the number 2.
 
-![Solution Example 1](solution_example_1.png)
-![Solution Example 2](solution_example_2.png)
-![Solution Example 3](solution_example_3.png)
-![Solution Example 4](solution_example_4.png)
-![Solution Example 5](solution_example_5.png)
-![Solution Example 6](solution_example_6.png)
-![Solution Example 7](solution_example_7.png)
-![Solution Example 8](solution_example_8.png)
+![Solution Example 1](images/solution/solution_example_1.png)
+![Solution Example 2](images/solution/solution_example_2.png)
+![Solution Example 3](images/solution/solution_example_3.png)
+![Solution Example 4](images/solution/solution_example_4.png)
+![Solution Example 5](images/solution/solution_example_5.png)
+![Solution Example 6](images/solution/solution_example_6.png)
+![Solution Example 7](images/solution/solution_example_7.png)
+![Solution Example 8](images/solution/solution_example_8.png)