Added power of subarrays solution.

README.md

@@ -253,6 +253,7 @@ programming challenges completed in other languages.
 - Minimized Maximum of Products Distributed to Any Store (https://leetcode.com/problems/minimized-maximum-of-products-distributed-to-any-store)
 - Remove K Digits (https://leetcode.com/problems/remove-k-digits)
 - Range Frequency Queries (https://leetcode.com/problems/range-frequency-queries)
+- Find the Power of K Size Sub-Arrays (https://leetcode.com/problems/find-the-power-of-k-size-subarrays-i)
 
 #### Hard
 

src/leetcode/mod.rs

@@ -100,3 +100,4 @@ mod square_numbers;
 mod minimized_maximum;
 mod remove_k_digits;
 mod range_freq;
+mod power_of_subarrays;

src/leetcode/power_of_subarrays.rs

@@ -0,0 +1,40 @@
+pub fn results_array(numbers: Vec<i32>, k: i32) -> Vec<i32> {
+    numbers
+        .windows(k as usize)
+        .map(|w| {
+            let (mut prev, mut max) = (w[0], w[0]);
+            for &val in w.iter().skip(1) {
+                if prev + 1 != val {
+                    return -1;
+                }
+                max = max.max(val);
+                prev = val;
+            }
+            max
+        })
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::results_array;
+
+    #[test]
+    fn non_consecutive_values() {
+        assert_eq!(vec![-1, -1], results_array(vec![2, 2, 2, 2, 2], 4))
+    }
+
+    #[test]
+    fn zipped_consecutive_values() {
+        assert_eq!(
+            vec![-1, 3, -1, 3, -1],
+            results_array(vec![3, 2, 3, 2, 3, 2], 2)
+        )
+    }
+
+    #[test]
+    fn k_equals_n() {
+        assert_eq!(vec![3], results_array(vec![2, 3], 2));
+        assert_eq!(vec![-1], results_array(vec![3, 2], 2))
+    }
+}