zig : upgrade codes && rust : add codes for chapter_searching and chapter_dynamic_programming. (#591)

* zig : update zig codes

* rust : add codes for linear_search and hashing_search

* rust : add codes for linear_search and hashing_search

* rust : add codes for chapter_dynamic_programming

codes/rust/include/list_node.rs

@@ -6,7 +6,9 @@
 
 use std::rc::Rc;
 use std::cell::RefCell;
+use std::collections::HashMap;
 
+#[derive(Debug)]
 pub struct ListNode<T> {
     pub val: T,
     pub next: Option<Rc<RefCell<ListNode<T>>>>,
@@ -19,4 +21,41 @@ impl<T> ListNode<T> {
             next: None,
         }))
     }
+    
+    /* Generate a linked list with an array */
+    pub fn arr_to_linked_list(array: &[T]) -> Option<Rc<RefCell<ListNode<T>>>> 
+    where
+        T: Copy + Clone,
+    {
+        let mut head = None;
+        let mut prev = None;
+        for item in array.iter().rev() {
+            let node = Rc::new(RefCell::new(ListNode {
+                val: *item,
+                next: prev.take(),
+            }));
+            prev = Some(node.clone());
+            head = Some(node);
+        }
+        head
+    }
+
+    /* Generate a hashmap with a linked_list */
+    pub fn linked_list_to_hashmap(
+        linked_list: Option<Rc<RefCell<ListNode<T>>>>,
+    ) -> HashMap<T, Rc<RefCell<ListNode<T>>>> 
+    where
+        T: std::hash::Hash + Eq + Copy + Clone
+    {
+        let mut hashmap = HashMap::new();
+        if let Some(node) = linked_list {
+            let mut current = Some(node.clone());
+            while let Some(cur) = current {
+                let borrow = cur.borrow();
+                hashmap.insert(borrow.val.clone(), cur.clone());
+                current = borrow.next.clone();
+            }
+        }
+        hashmap
+    }
 }