From 1e4049204e1b355ba10a6abc4b67bc47cc10b5b6 Mon Sep 17 00:00:00 2001
From: ridethepig <protonghost@163.com>
Date: Sat, 25 Feb 2023 10:41:19 +0000
Subject: [PATCH] part 2 except iterator

---
 week3/linked_list/src/linked_list.rs | 69 +++++++++++++++++++++-------
 week3/linked_list/src/main.rs        |  6 +++
 2 files changed, 59 insertions(+), 16 deletions(-)

diff --git a/week3/linked_list/src/linked_list.rs b/week3/linked_list/src/linked_list.rs
index c3a36d6..7527a1d 100644
--- a/week3/linked_list/src/linked_list.rs
+++ b/week3/linked_list/src/linked_list.rs
@@ -1,24 +1,24 @@
 use std::fmt;
 use std::option::Option;
 
-pub struct LinkedList {
-    head: Option<Box<Node>>,
+pub struct LinkedList<T> {
+    head: Option<Box<Node<T>>>,
     size: usize,
 }
 
-struct Node {
-    value: u32,
-    next: Option<Box<Node>>,
+struct Node<T> {
+    value: T,
+    next: Option<Box<Node<T>>>,
 }
 
-impl Node {
-    pub fn new(value: u32, next: Option<Box<Node>>) -> Node {
+impl<T> Node<T> {
+    pub fn new(value: T, next: Option<Box<Node<T>>>) -> Node<T> {
         Node {value: value, next: next}
     }
 }
 
-impl LinkedList {
-    pub fn new() -> LinkedList {
+impl<T> LinkedList<T> {
+    pub fn new() -> LinkedList<T> {
         LinkedList {head: None, size: 0}
     }
     
@@ -30,24 +30,26 @@ impl LinkedList {
         self.get_size() == 0
     }
     
-    pub fn push_front(&mut self, value: u32) {
-        let new_node: Box<Node> = Box::new(Node::new(value, self.head.take()));
+    pub fn push_front(&mut self, value: T) {
+        let new_node: Box<Node<T>> = Box::new(Node::new(value, self.head.take()));
         self.head = Some(new_node);
         self.size += 1;
     }
     
-    pub fn pop_front(&mut self) -> Option<u32> {
-        let node: Box<Node> = self.head.take()?;
+    pub fn pop_front(&mut self) -> Option<T> {
+        let node: Box<Node<T>> = self.head.take()?;
         self.head = node.next;
         self.size -= 1;
         Some(node.value)
     }
+
+
 }
 
 
-impl fmt::Display for LinkedList {
+impl<T:fmt::Display> fmt::Display for LinkedList<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let mut current: &Option<Box<Node>> = &self.head;
+        let mut current: &Option<Box<Node<T>>> = &self.head;
         let mut result = String::new();
         loop {
             match current {
@@ -62,7 +64,7 @@ impl fmt::Display for LinkedList {
     }
 }
 
-impl Drop for LinkedList {
+impl<T> Drop for LinkedList<T> {
     fn drop(&mut self) {
         let mut current = self.head.take();
         while let Some(mut node) = current {
@@ -71,5 +73,40 @@ impl Drop for LinkedList {
     }
 }
 
+impl<T:Clone> Clone for Node<T> {
+    fn clone(&self) -> Self {
+        Node::new(self.value.clone(), self.next.clone())
+    }
+}
 
+impl<T:Clone> Clone for LinkedList<T> {
+    fn clone(&self) -> LinkedList<T> {
+        let mut copy_list = LinkedList::new();
+        copy_list.size = self.size;
+        copy_list.head = self.head.clone();
+        // tricky recursive clone, Option clone-> Box clone-> Node clone -> Node.next clone(Box clone)
+        // I tried to implement tail-insertion, but it is impossible to realize that without unsafe...
+        copy_list
+    }
+}
+
+impl<T:PartialEq> PartialEq for LinkedList<T> {
+    fn eq(&self, other: &Self) -> bool {
+        if self.size != other.size {
+            return false;
+        }
+        let mut ptr = & self.head;
+        let mut ptr_other = & other.head;
+        while let Some(node) = ptr {
+            // well, as their size are the same, it's fine to assume that they reach the end at the same time
+            let node_other = ptr_other.as_ref().unwrap();
+            if node_other.value != node.value {
+                return false;
+            }
+            ptr = &node.next;
+            ptr_other = &node_other.next;
+        }
+        true
+    }
+}
 
diff --git a/week3/linked_list/src/main.rs b/week3/linked_list/src/main.rs
index 04226e9..981d23e 100644
--- a/week3/linked_list/src/main.rs
+++ b/week3/linked_list/src/main.rs
@@ -15,6 +15,12 @@ fn main() {
     println!("size: {}", list.get_size());
     println!("{}", list.to_string()); // ToString impl for anything impl Display
 
+    let mut list2 = list.clone();
+    println!("Right after clone: list == list2 ?= {}", list == list2);
+    list2.pop_front();
+    println!("list2.pop_front: {}", list2);
+    println!("list == list2 ?= {}", list == list2);
+    
     // If you implement iterator trait:
     //for val in &list {
     //    println!("{}", val);