GuessNumberHigherorLower

Author: FeiCoding

(#374)GuessNumberHigherorLower/GuessNumberHigherorLower.java

@@ -0,0 +1,14 @@
+public class Solution extends GuessGame {
+    public int guessNumber(int n) {
+        int left = 1;
+        int right = n;
+        return helper(n, left, right);
+    }
+    private int helper(int n, int left, int right){
+        if(left > right) return -1;
+        int mid = left + (right - left) / 2;
+        if(guess(mid) == 0) return mid;
+        if(guess(mid) == -1) return helper(n, left, mid - 1);
+        else return helper(n, mid + 1, right);
+    }
+}

(#704)BinarySearch/BinarySearch.java

@@ -0,0 +1,15 @@
+class Solution {
+    public int search(int[] nums, int target) {
+        return search(nums, target, 0, nums.length - 1);
+    }
+    
+    private int search(int []nums, int target, int left, int right){
+        if(left > right) return -1;
+        int mid = left + (right - left) / 2;
+        if(nums[mid] == target) return mid;
+        else if(nums[mid] < target){
+            return search(nums, target, mid + 1, right);
+        }
+        else return search(nums, target, left, mid - 1);
+    }
+}