Merge pull request wangzheng0822#127 from yangchuz/master

Basic binary search implementation in Scala
ddzcoeur · Nov 2, 2018 · 3531564 · 3531564
2 parents b0a8643 + 44a2376
commit 3531564
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diff --git a/scala/15_bsearch/BSearch.scala b/scala/15_bsearch/BSearch.scala
@@ -0,0 +1,18 @@
+object BSearch {
+    def search(nums: Array[Int], target: Int): Int = {
+        var low = 0
+        var high = nums.length - 1
+        while(low <= high){
+            val mid = low + ((high - low) >> 2)
+            if(nums(mid) > target){
+                high = mid - 1
+            } else if (nums(mid) < target){
+                low = mid + 1
+            } else {
+                return mid
+            }
+        }
+
+        return -1
+    }
+}
diff --git a/scala/15_bsearch/BSearchRecursive.scala b/scala/15_bsearch/BSearchRecursive.scala
@@ -0,0 +1,20 @@
+object BSearchRecursive {
+    def search(nums: Array[Int], target: Int): Int = {
+        return searchInternal(nums, target, 0, nums.length - 1)
+    }
+
+    def searchInternal(nums:Array[Int], target: Int, low: Int, high: Int): Int = {
+        if(low <= high){
+            val mid = low + ((high - low) >> 2)
+            if(nums(mid) > target){
+                searchInternal(nums, target, low, mid - 1)
+            } else if (nums(mid) < target){                
+                searchInternal(nums, target, mid + 1, high)
+            } else {
+                return mid
+            }
+        }else{
+            return -1    
+        }
+    }
+}