feat: 33_search_in_rotated_sorted_array

33_search_in_rotated_sorted_array/main.cpp

@@ -0,0 +1,55 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+   public:
+    int recursive(vector<int>& nums, int target, int left, int right) {
+        int mid = (right + left) / 2;
+
+        if (target == nums[mid]) {
+            return mid;
+        }
+
+        if (left >= right) {
+            return -1;
+        }
+
+        if (left + 1 == right) {
+            if (target == nums[left]) return left;
+            if (target == nums[right]) return right;
+        }
+
+        // the left part is sorted && target is in the left part
+        if (nums[left] <= target && target <= nums[mid]) {
+            if (binary_search(nums.begin() + left, nums.begin() + mid + 1, target)) {
+                return lower_bound(nums.begin() + left, nums.begin() + mid + 1, target) - nums.begin();
+            }
+            return -1;
+        }
+
+        // the right part is sorted && target is in the right part
+        if (nums[mid] <= target && target <= nums[right]) {
+            if (binary_search(nums.begin() + mid, nums.begin() + right + 1, target)) {
+                return lower_bound(nums.begin() + mid, nums.begin() + right + 1, target) - nums.begin();
+            }
+            return -1;
+        }
+
+        // target is not in a sorted part
+        if (nums[left] < nums[mid]) {  // the right part is not sorted
+            return recursive(nums, target, mid, right);
+        } else {  // the left part is not sorted
+            return recursive(nums, target, left, mid);
+        }
+    }
+
+    int search(vector<int>& nums, int target) {
+        return recursive(nums, target, 0, nums.size() - 1);
+    }
+};
+
+int main() {
+    vector<int> vec{3, 1};
+    Solution().search(vec, 1);
+    return 0;
+}