Create 704.BinarySearch.cpp

Author: reza-ebrahimi

704.BinarySearch.cpp

@@ -0,0 +1,57 @@
+///
+/// LeetCode 
+/// By Reza Ebrahimi <reza.ebrahimi.dev@gmail.com>
+///
+/// Binary Search Problem
+/// https://leetcode.com/problems/binary-search
+///
+/// Runtime: 40 ms, faster than 39.64% of C++ online submissions for Binary Search.
+/// Memory Usage: 32 MB, less than 5.31% of C++ online submissions for Binary Search.
+/// Time Submitted: 06/22/2021 00:07
+///
+
+class Solution {
+public:
+    int search(vector<int>& nums, int target) {
+        return binary_search_ex(move(nums), target, 0);
+    }
+    
+    int binary_search_ex(vector<int> nums, int target, int offset) {
+        int ret = -1;
+        int len = nums.size();
+        int mid = len / 2;
+
+        sort(nums.begin(), nums.end());
+
+        if (len <= 0) {
+            return -1;
+        } else if (len == 1 && target == nums[mid]) {
+            return mid + offset;
+        } else if (len == 1 && target != nums[mid]) {
+            return -1;
+        }
+
+        if (target < nums[mid]) {
+            std::vector<int> vec(nums.begin(), nums.begin() + mid);
+            ret = binary_search_ex(vec, target, 0);
+        } else if (target > nums[mid]) {
+            std::vector<int> vec(nums.begin() + mid, nums.end());
+            ret = binary_search_ex(vec, target, mid);
+        } else {
+            return mid + offset;
+        }
+
+        len = len - mid;
+        mid = len / 2;
+
+        if (mid == 0 && target == nums[mid]) {
+            return mid + offset;
+        }
+
+        if (ret == -1) {
+            return ret;
+        }
+
+        return ret + offset;
+    }    
+};