이슈 #133에서 솔루션 추가

LeetCode/Guess_Number_Higher_or_Lower.cpp

@@ -0,0 +1,30 @@
+/** 
+ * Forward declaration of guess API.
+ * @param  num   your guess
+ * @return 	     -1 if num is higher than the picked number
+ *			      1 if num is lower than the picked number
+ *               otherwise return 0
+ * int guess(int num);
+ */
+
+class Solution {
+public:
+    int guessNumber(int n) {
+        int left = 1;
+        int right = n;
+
+        while (left <= right) {
+            int mid = left + (right - left) / 2;
+            int res = guess(mid);
+            if (res == 0) {
+                return mid;
+            } else if (res == 1) {
+                left = mid + 1;
+            } else if (res == -1) {
+                right = mid - 1;
+            }
+        }
+
+        return -1;
+    }
+};