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1 | | -package basics; |
2 | | -import java.util.Arrays; |
3 | | - |
4 | | -public class BinarySearch { |
5 | | - |
6 | | - public static void main(String[] args) { |
7 | | - |
8 | | - int arr[] = {10, 20, 15, 22, 35}; |
9 | | - Arrays.sort(arr); |
10 | | - |
11 | | - int key = 35; |
12 | | - int res = Arrays.binarySearch(arr, key); |
13 | | - if(res >= 0){ |
14 | | - System.out.println(key + " found at index = "+ res); |
15 | | - } else { |
16 | | - System.out.println(key + " not found"); |
17 | | - } |
| 1 | +// Java implementation of iterative Binary Search |
| 2 | + |
| 3 | +import java.io.*; |
| 4 | + |
| 5 | +class BinarySearch { |
| 6 | + |
| 7 | + // Returns index of x if it is present in arr[]. |
| 8 | + int binarySearch(int arr[], int x) |
| 9 | + { |
| 10 | + int l = 0, r = arr.length - 1; |
| 11 | + while (l <= r) { |
| 12 | + int m = l + (r - l) / 2; |
| 13 | + |
| 14 | + // Check if x is present at mid |
| 15 | + if (arr[m] == x) |
| 16 | + return m; |
| 17 | + |
| 18 | + // If x greater, ignore left half |
| 19 | + if (arr[m] < x) |
| 20 | + l = m + 1; |
| 21 | + |
| 22 | + // If x is smaller, ignore right half |
| 23 | + else |
| 24 | + r = m - 1; |
| 25 | + } |
| 26 | + |
| 27 | + // If we reach here, then element was |
| 28 | + // not present |
| 29 | + return -1; |
| 30 | + } |
| 31 | + |
| 32 | + // Driver code |
| 33 | + public static void main(String args[]) |
| 34 | + { |
| 35 | + BinarySearch ob = new BinarySearch(); |
| 36 | + int arr[] = { 2, 3, 4, 10, 40 }; |
| 37 | + int n = arr.length; |
| 38 | + int x = 10; |
| 39 | + int result = ob.binarySearch(arr, x); |
| 40 | + if (result == -1) |
| 41 | + System.out.println( |
| 42 | + "Element is not present in array"); |
| 43 | + else |
| 44 | + System.out.println("Element is present at " |
| 45 | + + "index " + result); |
18 | 46 | } |
19 | 47 | } |
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