diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index ddeb738..bd6cbf4 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -24,4 +24,5 @@ mod p2171_removing_minimum_number_of_magic_beans;
 mod p2809_minimum_time_to_make_array_sum_at_most_x;
 mod p2788_split_strings_by_separator;
 mod p410_split_array_largest_sum;
-mod p670_maximum_swap;
\ No newline at end of file
+mod p670_maximum_swap;
+mod p2765_longest_alternating_subarray;
\ No newline at end of file
diff --git a/src/problem/p2765_longest_alternating_subarray.rs b/src/problem/p2765_longest_alternating_subarray.rs
new file mode 100644
index 0000000..86fc0e0
--- /dev/null
+++ b/src/problem/p2765_longest_alternating_subarray.rs
@@ -0,0 +1,40 @@
+/**
+ * [2765] Longest Alternating Subarray
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn alternating_subarray(nums: Vec<i32>) -> i32 {
+        let mut result = -1;
+
+        for i in 0..nums.len() {
+            for j in i + 1..nums.len() {
+                if nums[j] - nums[i] != ((j - i) % 2) as i32 {
+                    break;
+                }
+
+                result = result.max((j - i + 1) as i32);
+            }
+        }
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2765() {
+        assert_eq!(Solution::alternating_subarray(vec![2,3,4,3,4]), 4);
+        assert_eq!(Solution::alternating_subarray(vec![4,5,6]), 2);
+        assert_eq!(Solution::alternating_subarray(vec![21,9,5]), -1);
+        assert_eq!(Solution::alternating_subarray(vec![21,22]), 2);
+    }
+}