solve 21

1 files changed, 40 insertions, 0 deletions

diff --git a/src/list.rs b/src/list.rs
new file mode 100644
index 0000000..d033cfe
--- /dev/null
+++ b/src/list.rs
@@ -0,0 +1,40 @@
+#[derive(PartialEq, Eq, Clone, Debug)]
+pub struct ListNode {
+    pub val: i32,
+    pub next: Option<Box<ListNode>>
+}
+//
+impl ListNode {
+    #[inline]
+    pub fn new(val: i32) -> Self {
+        ListNode {
+            next: None,
+            val
+        }
+    }
+}
+
+pub fn vector2list(vec: Vec<i32>) -> Option<Box<ListNode>> {
+    let mut result: Option<Box<ListNode>> = None;
+    for i in 0..vec.len() {
+        let mut new_result = Some(Box::new(ListNode::new(vec[vec.len() - i - 1])));
+        new_result.as_mut().unwrap().next = result;
+        result = new_result;
+    }
+    result
+}
+
+pub fn list2vector(lst: Option<Box<ListNode>>) -> Vec<i32> {
+    let mut result: Vec<i32> = Vec::new();
+    let mut cur = &lst;
+    loop {
+        match cur {
+            None => break,
+            Some(node) => {
+                result.push(node.val);
+                cur = &node.next;
+            },
+        }
+    }
+    result
+}
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