Add C++ implementation

Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>

Author: begeekmyfriend

0069_sqrt/sqrt.c

@@ -51,26 +51,26 @@ static double mySqrt(double n)
 }
 #endif
 
-static int mySqrt(int x)
+int mySqrt(int x)
 {
     if (x == 0) {
         return 0;
     }
 
-    unsigned int left = 1;
-    unsigned int right = (unsigned int) x;
-    unsigned int mid = left + (right - left) / 2;
+    unsigned int lo = 1;
+    unsigned int hi = (unsigned int) x;
+    unsigned int mid = lo + (hi - lo) / 2;
     for (; ;) {
         if (mid > x/mid) {
-            right = mid;
+            hi = mid;
         } else {
             if (mid + 1 > x/(mid + 1)) {
                 break;
             } else {
-                left = mid;
+                lo = mid;
             }
         }
-        mid = left + (right - left) / 2;
+        mid = lo + (hi - lo) / 2;
     }
 
     return mid;

0069_sqrt/sqrt.cc

@@ -0,0 +1,29 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+class Solution {
+public:
+    int mySqrt(int x) {
+        if (x == 0) {
+            return 0;
+        }
+
+        unsigned int lo = 1, hi = x;
+        unsigned int mid = (lo + hi) / 2;
+        for (; ;) {
+            if (mid > x / mid) {
+                hi = mid;
+            } else {
+                if (mid + 1 > x / (mid + 1)) {
+                    break;
+                } else {
+                    lo = mid;
+                }
+            }
+            mid = (lo + hi) / 2;
+        }
+
+        return mid;
+    }
+};