Added merge nodes solution.

README.md

@@ -248,7 +248,8 @@ programming challenges completed in other languages.
 - [Container With Most Water](https://leetcode.com/problems/container-with-most-water)
 - [Max Chunks to Make Sorted](https://leetcode.com/problems/max-chunks-to-make-sorted)
 - [Valid Sudoku](https://leetcode.com/problems/valid-sudoku)
-
+- [Merge Nodes In Between Zeroes](https://leetcode.com/problems/merge-nodes-in-between-zeros/)
+
 #### Hard
 
 - [Kth Smallest Pair Distance](https://leetcode.com/problems/find-k-th-smallest-pair-distance)

src/leetcode/merge_nodes.rs

@@ -0,0 +1,45 @@
+#[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 }
+    }
+}
+
+pub fn merge_nodes(mut head: Option<Box<ListNode>>) -> Option<Box<ListNode>> {
+    let mut curr = head.as_deref_mut();
+    while let Some(curr_node) = curr.take() {
+        let mut next_node = curr_node.next.take()?;
+        let tail = next_node.next.take();
+        curr_node.next = tail;
+
+        if next_node.val == 0 {
+            curr = curr_node.next.as_deref_mut();
+        } else {
+            curr_node.val += next_node.val;
+            curr = Some(curr_node);
+        }
+    }
+    head
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn merges_values_between_zeroes() {
+        let tail = Box::new(ListNode::new(0));
+        let mut number = Box::new(ListNode::new(5));
+        number.next = Some(tail);
+        let mut head = Box::new(ListNode::new(0));
+        head.next = Some(number);
+
+        assert_eq!(Some(Box::new(ListNode::new(5))), merge_nodes(Some(head)))
+    }
+}

src/leetcode/mod.rs

@@ -156,3 +156,4 @@ mod search_insert;
 mod smallest_letter;
 mod negative_numbers;
 mod guess_number;
+mod merge_nodes;