1752. Check if Array Is Sorted and Rotated: AC

Author: tan-wei

src/solution/mod.rs

@@ -1320,3 +1320,4 @@ mod s1748_sum_of_unique_elements;
 mod s1749_maximum_absolute_sum_of_any_subarray;
 mod s1750_minimum_length_of_string_after_deleting_similar_ends;
 mod s1751_maximum_number_of_events_that_can_be_attended_ii;
+mod s1752_check_if_array_is_sorted_and_rotated;

src/solution/s1752_check_if_array_is_sorted_and_rotated.rs

@@ -0,0 +1,91 @@
+/**
+ * [1752] Check if Array Is Sorted and Rotated
+ *
+ * Given an array nums, return true if the array was originally sorted in non-decreasing order, then rotated some number of positions (including zero). Otherwise, return false.
+ * There may be duplicates in the original array.
+ * Note: An array A rotated by x positions results in an array B of the same length such that A[i] == B[(i+x) % A.length], where % is the modulo operation.
+ *  
+ * Example 1:
+ *
+ * Input: nums = [3,4,5,1,2]
+ * Output: true
+ * Explanation: [1,2,3,4,5] is the original sorted array.
+ * You can rotate the array by x = 3 positions to begin on the the element of value 3: [3,4,5,1,2].
+ *
+ * Example 2:
+ *
+ * Input: nums = [2,1,3,4]
+ * Output: false
+ * Explanation: There is no sorted array once rotated that can make nums.
+ *
+ * Example 3:
+ *
+ * Input: nums = [1,2,3]
+ * Output: true
+ * Explanation: [1,2,3] is the original sorted array.
+ * You can rotate the array by x = 0 positions (i.e. no rotation) to make nums.
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= nums.length <= 100
+ * 	1 <= nums[i] <= 100
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/check-if-array-is-sorted-and-rotated/
+// discuss: https://leetcode.com/problems/check-if-array-is-sorted-and-rotated/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn check(nums: Vec<i32>) -> bool {
+        let mut count = 0;
+
+        for (i, v) in nums.iter().enumerate() {
+            if v > &nums[(i + 1) % nums.len()] {
+                count += 1;
+            }
+            if count > 1 {
+                return false;
+            }
+        }
+
+        true
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1752_example_1() {
+        let nums = vec![3, 4, 5, 1, 2];
+
+        let result = true;
+
+        assert_eq!(Solution::check(nums), result);
+    }
+
+    #[test]
+    fn test_1752_example_2() {
+        let nums = vec![2, 1, 3, 4];
+
+        let result = false;
+
+        assert_eq!(Solution::check(nums), result);
+    }
+
+    #[test]
+    fn test_1752_example_3() {
+        let nums = vec![1, 2, 3];
+
+        let result = true;
+
+        assert_eq!(Solution::check(nums), result);
+    }
+}