feat: add rust solution to lc problem: No.0019

No.0019.Remove Nth Node From End of List

Author: YangFong

solution/0000-0099/0019.Remove Nth Node From End of List/README.md

@@ -226,6 +226,43 @@ def remove_nth_from_end(head, n)
 end
 ```
 
+### **Rust**
+
+```rust
+// Definition for singly-linked list.
+// #[derive(PartialEq, Eq, Clone, Debug)]
+// pub struct ListNode {
+//   pub val: i32,
+//   pub next: Option<Box<ListNode>>
+// }
+//
+// impl ListNode {
+//   #[inline]
+//   fn new(val: i32) -> Self {
+//     ListNode {
+//       next: None,
+//       val
+//     }
+//   }
+// }
+impl Solution {
+    pub fn remove_nth_from_end(head: Option<Box<ListNode>>, n: i32) -> Option<Box<ListNode>> {
+        let mut dummy = Some(Box::new(ListNode { val: 0, next: head }));
+        let mut slow = &mut dummy;
+        let mut fast = &slow.clone();
+        for _ in 0..=n {
+            fast = &fast.as_ref().unwrap().next;
+        }
+        while fast.is_some() {
+            fast = &fast.as_ref().unwrap().next;
+            slow = &mut slow.as_mut().unwrap().next;
+        }
+        slow.as_mut().unwrap().next = slow.as_mut().unwrap().next.as_mut().unwrap().next.take();
+        dummy.unwrap().next
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0000-0099/0019.Remove Nth Node From End of List/README_EN.md

@@ -214,6 +214,43 @@ def remove_nth_from_end(head, n)
 end
 ```
 
+### **Rust**
+
+```rust
+// Definition for singly-linked list.
+// #[derive(PartialEq, Eq, Clone, Debug)]
+// pub struct ListNode {
+//   pub val: i32,
+//   pub next: Option<Box<ListNode>>
+// }
+//
+// impl ListNode {
+//   #[inline]
+//   fn new(val: i32) -> Self {
+//     ListNode {
+//       next: None,
+//       val
+//     }
+//   }
+// }
+impl Solution {
+    pub fn remove_nth_from_end(head: Option<Box<ListNode>>, n: i32) -> Option<Box<ListNode>> {
+        let mut dummy = Some(Box::new(ListNode { val: 0, next: head }));
+        let mut slow = &mut dummy;
+        let mut fast = &slow.clone();
+        for _ in 0..=n {
+            fast = &fast.as_ref().unwrap().next;
+        }
+        while fast.is_some() {
+            fast = &fast.as_ref().unwrap().next;
+            slow = &mut slow.as_mut().unwrap().next;
+        }
+        slow.as_mut().unwrap().next = slow.as_mut().unwrap().next.as_mut().unwrap().next.take();
+        dummy.unwrap().next
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0000-0099/0019.Remove Nth Node From End of List/Solution.rs

@@ -0,0 +1,32 @@
+// Definition for singly-linked list.
+// #[derive(PartialEq, Eq, Clone, Debug)]
+// pub struct ListNode {
+//   pub val: i32,
+//   pub next: Option<Box<ListNode>>
+// }
+//
+// impl ListNode {
+//   #[inline]
+//   fn new(val: i32) -> Self {
+//     ListNode {
+//       next: None,
+//       val
+//     }
+//   }
+// }
+impl Solution {
+    pub fn remove_nth_from_end(head: Option<Box<ListNode>>, n: i32) -> Option<Box<ListNode>> {
+        let mut dummy = Some(Box::new(ListNode { val: 0, next: head }));
+        let mut slow = &mut dummy;
+        let mut fast = &slow.clone();
+        for _ in 0..=n {
+            fast = &fast.as_ref().unwrap().next;
+        }
+        while fast.is_some() {
+            fast = &fast.as_ref().unwrap().next;
+            slow = &mut slow.as_mut().unwrap().next;
+        }
+        slow.as_mut().unwrap().next = slow.as_mut().unwrap().next.as_mut().unwrap().next.take();
+        dummy.unwrap().next
+    }
+}