└── Binary search in java


/Binary search in java:
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 1 | // Java implementation of iterative Binary Search
 2 | class BinarySearch {
 3 | 	// Returns index of x if it is present in arr[l....r], else return -1
 4 | 	int binarySearch(int arr[], int l, int r, int x)
 5 | 	{
 6 | 		while (l <= r) {
 7 | 			int mid = (l + r) / 2;
 8 | 
 9 | 			// If the element is present at the
10 | 			// middle itself
11 | 			if (arr[mid] == x) {
12 | 				return mid;
13 | 
14 | 			// If element is smaller than mid, then
15 | 			// it can only be present in left subarray
16 | 			// so we decrease our r pointer to mid - 1 
17 | 			} else if (arr[mid] > x) {
18 | 				r = mid - 1;
19 | 
20 | 			// Else the element can only be present
21 | 			// in right subarray
22 | 			// so we increase our l pointer to mid + 1
23 | 			} else {
24 | 			l = mid + 1;
25 | 			} 
26 | 		}
27 | 
28 | 		// We reach here when element is not present
29 | 		// in array
30 | 		return -1;
31 | 	}
32 | 
33 | 	// Driver method to test above
34 | 	public static void main(String args[])
35 | 	{
36 | 		BinarySearch ob = new BinarySearch();
37 | 
38 | 		int arr[] = { 2, 3, 4, 10, 40 };
39 | 		int n = arr.length;
40 | 		int x = 10;
41 | 		int result = ob.binarySearch(arr, 0, n - 1, x);
42 | 
43 | 		if (result == -1)
44 | 			System.out.println("Element not present");
45 | 		else
46 | 			System.out.println("Element found at index "
47 | 							+ result);
48 | 	}
49 | }
50 | 


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