374. Guess Number Higher or Lower

Author: VinayByte

374.GuessNumberHigherorLower

@@ -0,0 +1,26 @@
+/** 
+ * The API guess is defined in the parent class.
+ * @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
+ * fun guess(num:Int):Int {}
+ */
+//https://leetcode.com/problems/guess-number-higher-or-lower/description/
+//Binary search: time O(log n)
+class Solution:GuessGame() {
+    override fun guessNumber(n:Int):Int {
+        var low = 1
+        var high = n
+        while(low <= high){
+            val mid = low + (high - low)/2
+            val guess = guess(mid)
+            when(guess){
+                0 -> return mid
+                -1 -> high = mid -1
+                1 -> low = mid + 1
+            }
+        }
+        return -1
+    }
+}