Merge pull request #1671 from Jack-Zhang-1314/patch-4

update 707.设计链表 about rust

problems/0707.设计链表.md

@@ -1240,6 +1240,94 @@ class MyLinkedList() {
 }
 ```
 
+Rust:
+
+```rust
+#[derive(Debug)]
+pub struct MyLinkedList {
+    pub val: i32,
+    pub next: Option<Box<MyLinkedList>>,
+}
+
+impl MyLinkedList {
+    fn new() -> Self {
+        // 增加头节点
+        MyLinkedList { val: 0, next: None }
+    }
+
+    fn get(&self, index: i32) -> i32 {
+        if index < 0 {
+            return -1;
+        }
+        let mut i = 0;
+        let mut cur = &self.next;
+        while let Some(node) = cur {
+            if i == index {
+                return node.val;
+            }
+            i += 1;
+            cur = &node.next;
+        }
+        -1
+    }
+
+    fn add_at_head(&mut self, val: i32) {
+        let new_node = Box::new(MyLinkedList {
+            val,
+            next: self.next.take(),
+        });
+        self.next = Some(new_node);
+    }
+
+    fn add_at_tail(&mut self, val: i32) {
+        let new_node = Box::new(MyLinkedList { val, next: None });
+        let mut last_node = &mut self.next;
+        while let Some(node) = last_node {
+            last_node = &mut node.next;
+        }
+        *last_node = Some(new_node);
+    }
+
+    fn add_at_index(&mut self, index: i32, val: i32) {
+        if index <= 0 {
+            self.add_at_head(val);
+        } else {
+            let mut i = 0;
+            let mut cur = &mut self.next;
+            while let Some(node) = cur {
+                if i + 1 == index {
+                    let new_node = Box::new(MyLinkedList {
+                        val,
+                        next: node.next.take(),
+                    });
+                    node.next = Some(new_node);
+                    break;
+                }
+                i += 1;
+                cur = &mut node.next;
+            }
+        }
+    }
+
+    fn delete_at_index(&mut self, index: i32) {
+        if index < 0 {
+            return;
+        }
+
+        let mut i = 0;
+        let mut cur = self;
+        while let Some(node) = cur.next.take() {
+            if i == index {
+                cur.next = node.next;
+                break;
+            }
+            i += 1;
+            cur.next = Some(node);
+            cur = cur.next.as_mut().unwrap();
+        }
+    }
+}
+```
 
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