solution: Search in Rotated Sorted Array

Author: Kilerd

src/main.rs

@@ -22,6 +22,7 @@ mod remove_duplicates_from_sorted_array;
 mod remove_element;
 mod reverse_integer;
 mod robot_return_to_origin;
+mod search_in_rotated_sorted_array;
 mod self_dividing_numbers;
 mod sort_array_by_parity;
 mod sort_array_by_parity_ii;

src/search_in_rotated_sorted_array.rs

@@ -0,0 +1,90 @@
+/// @number 33
+/// @title Search in Rotated Sorted Array
+/// @url https://leetcode.com/problems/search-in-rotated-sorted-array/
+/// @difficulty Medium
+
+struct Solution;
+
+impl Solution {
+    pub fn rotated_index(nums: &Vec<i32>, start: usize, end: usize) -> usize {
+        if nums[start] < nums[end] {
+            start
+        } else {
+            let mid = (end + start) / 2;
+            if mid == start {
+                return mid;
+            }
+            if nums[mid] < nums[start] {
+                Solution::rotated_index(nums, start, mid)
+            } else {
+                Solution::rotated_index(nums, mid, end)
+            }
+        }
+    }
+
+    pub fn search(nums: Vec<i32>, target: i32) -> i32 {
+        if nums.len() == 0 {
+            return -1;
+        }
+
+        let rotated_index = Solution::rotated_index(&nums, 0, nums.len() - 1);
+
+        let index = if nums[0] <= target && target <= nums[rotated_index] {
+            nums[0..=rotated_index].binary_search(&target)
+        } else if rotated_index < nums.len() - 1 {
+            if nums[rotated_index + 1] <= target && target <= nums[nums.len() - 1] {
+                nums[rotated_index..nums.len()]
+                    .binary_search(&target)
+                    .map(|i| i + rotated_index)
+            } else {
+                Err(0)
+            }
+        } else {
+            Err(0)
+        };
+
+        if let Ok(index) = index {
+            index as i32
+        } else {
+            -1
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::search_in_rotated_sorted_array::Solution;
+
+    #[test]
+    fn test_rotated() {
+        assert_eq!(3, Solution::rotated_index(&vec![4, 5, 6, 7, 0, 1, 2], 0, 6))
+    }
+
+    #[test]
+    fn test() {
+        assert_eq!(4, Solution::search(vec![4, 5, 6, 7, 0, 1, 2], 0));
+    }
+
+    #[test]
+    fn test2() {
+        assert_eq!(-1, Solution::search(vec![4, 5, 6, 7, 0, 1, 2], 3));
+    }
+
+    #[test]
+    fn test3() {
+        assert_eq!(7, Solution::search(vec![4, 5, 6, 7, 0, 1, 2, 3], 3));
+    }
+    #[test]
+    fn test4() {
+        assert_eq!(-1, Solution::search(vec![], 3));
+    }
+
+    #[test]
+    fn test5() {
+        assert_eq!(-1, Solution::search(vec![1], 3));
+    }
+    #[test]
+    fn test6() {
+        assert_eq!(0, Solution::search(vec![1], 1));
+    }
+}