diff --git a/src/solution/mod.rs b/src/solution/mod.rs
index 854953f..e2e4d33 100644
--- a/src/solution/mod.rs
+++ b/src/solution/mod.rs
@@ -14,3 +14,4 @@ mod s0007_reverse_integer;
 mod s0004_median_of_two_sorted_arrays;
 mod s0743_network_delay_time;
 mod s0447_number_of_boomerangs;
+mod s2085_count_common_words_with_one_occurrence;
diff --git a/src/solution/s2085_count_common_words_with_one_occurrence.rs b/src/solution/s2085_count_common_words_with_one_occurrence.rs
new file mode 100644
index 0000000..1d3ee2d
--- /dev/null
+++ b/src/solution/s2085_count_common_words_with_one_occurrence.rs
@@ -0,0 +1,86 @@
+/**
+ * [2085] Count Common Words With One Occurrence
+ *
+ * Given two string arrays words1 and words2, return the number of strings that appear exactly once in each of the two arrays.
+ *  
+ * <strong class="example">Example 1:
+ * 
+ * Input: words1 = ["leetcode","is","amazing","as","is"], words2 = ["amazing","leetcode","is"]
+ * Output: 2
+ * Explanation:
+ * - "leetcode" appears exactly once in each of the two arrays. We count this string.
+ * - "amazing" appears exactly once in each of the two arrays. We count this string.
+ * - "is" appears in each of the two arrays, but there are 2 occurrences of it in words1. We do not count this string.
+ * - "as" appears once in words1, but does not appear in words2. We do not count this string.
+ * Thus, there are 2 strings that appear exactly once in each of the two arrays.
+ * 
+ * <strong class="example">Example 2:
+ * 
+ * Input: words1 = ["b","bb","bbb"], words2 = ["a","aa","aaa"]
+ * Output: 0
+ * Explanation: There are no strings that appear in each of the two arrays.
+ * 
+ * <strong class="example">Example 3:
+ * 
+ * Input: words1 = ["a","ab"], words2 = ["a","a","a","ab"]
+ * Output: 1
+ * Explanation: The only string that appears exactly once in each of the two arrays is "ab".
+ * 
+ *  
+ * Constraints:
+ * 
+ * 	1 <= words1.length, words2.length <= 1000
+ * 	1 <= words1[i].length, words2[j].length <= 30
+ * 	words1[i] and words2[j] consists only of lowercase English letters.
+ * 
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.cn/problems/count-common-words-with-one-occurrence/
+// discuss: https://leetcode.cn/problems/count-common-words-with-one-occurrence/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+use std::collections::HashMap;
+
+impl Solution {
+    pub fn count_words(words1: Vec<String>, words2: Vec<String>) -> i32 {
+        let mut dict = HashMap::new();
+
+        for i in &words1 {
+            match dict.get(i) {
+                None => {
+                    dict.insert(i, 0);}
+                Some(_) => {
+                    dict.insert(i ,1);
+                }
+            }
+        }
+
+        for i in &words2 {
+            match dict.get(i) {
+                None => {}
+                Some(value) => {
+                    if *value == 0 {
+                        dict.insert(i, 2);
+                    } else if *value == 2{
+                        dict.insert(i, 1);
+                    }
+                }
+            }
+        }
+
+        dict.values().filter(|x| {**x == 2}).count() as i32
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2085() {
+    }
+}