20250427 finished.

src/problem/mod.rs

@@ -621,3 +621,5 @@ mod p2845_count_of_interesting_subarrays;
 
 mod p1287_element_appearing_more_than_25_in_sorted_array;
 mod p2444_count_subarrays_with_fixed_bounds;
+
+mod p3392_count_subarrays_of_length_three_with_a_condition;

src/problem/p3392_count_subarrays_of_length_three_with_a_condition.rs

@@ -0,0 +1,35 @@
+/**
+ * [3392] Count Subarrays of Length Three With a Condition
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn count_subarrays(nums: Vec<i32>) -> i32 {
+        nums.iter()
+            .enumerate()
+            .skip(2)
+            .filter_map(|(i, &v)| {
+                if (nums[i - 2] + v) * 2 == nums[i - 1] {
+                    Some(())
+                } else {
+                    None
+                }
+            })
+            .count() as i32
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_3392() {
+        assert_eq!(1, Solution::count_subarrays(vec![1, 2, 1, 4, 1]));
+        assert_eq!(0, Solution::count_subarrays(vec![1, 1, 1]));
+    }
+}