[0.binarySearch]

Author: YILING

LeetCode.xcodeproj/project.pbxproj

@@ -8,6 +8,7 @@
 
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 				6D668CEC1E96878E0001054C /* 0_Fibonacci.cpp */,
 				6D668CED1E96878E0001054C /* 0_Fibonacci.hpp */,
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 				6D668CEE1E96878E0001054C /* 0_Fibonacci.cpp in Sources */,
+				6D668CF11E969CD30001054C /* 0_BinarySearch.cpp in Sources */,
 				6DEF8F5F1E75A0EC0028351C /* main.cpp in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

LeetCode/0_BinarySearch.cpp

@@ -0,0 +1,39 @@
+//
+//  0_BinarySearch.cpp
+//  LeetCode
+//
+//  Created by Yi-Ling Wu on 06/04/2017.
+//  Copyright © 2017 YILING. All rights reserved.
+//
+
+#include "0_BinarySearch.hpp"
+
+int BinarySearch::BinarySearchIterative(int *array, int length, int num) {
+    int left = 0, right = length - 1;
+    while (left <= right) {
+        int middle = (left + right) / 2;
+        if (array[middle] == num) {
+            return middle;
+        }
+
+        if (array[middle] > num) {
+            right = middle - 1;
+        } else {
+            left = middle + 1;
+        }
+    }
+    return -1;
+}
+
+int BinarySearch::BinaarySearchDeviceAndConquer(int *array, int num, int left, int right) {
+    if (left > right) return -1;
+    int middle = (left + right) / 2;
+
+    if (array[middle] == num) return middle;
+
+    if (array[middle] > num)
+        return BinarySearch::BinaarySearchDeviceAndConquer(array, num, left, middle - 1);
+    else
+        return BinarySearch::BinaarySearchDeviceAndConquer(array, num, middle + 1, right);
+    return 0;
+}

LeetCode/0_BinarySearch.hpp

@@ -0,0 +1,20 @@
+//
+//  0_BinarySearch.hpp
+//  LeetCode
+//
+//  Created by Yi-Ling Wu on 06/04/2017.
+//  Copyright © 2017 YILING. All rights reserved.
+//
+
+#ifndef __BinarySearch_hpp
+#define __BinarySearch_hpp
+
+#include <stdio.h>
+
+class BinarySearch {
+public:
+    static int BinarySearchIterative(int *array, int length, int num);
+    static int BinaarySearchDeviceAndConquer(int *array, int num, int left, int right);
+};
+
+#endif /* __BinarySearch_hpp */