Created
February 20, 2013 19:42
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Given a sorted array of integers array and an integer key, return the index of the first instance of key in the array. If key is not present in array, you should return -1. For example, given the array [-10, -2, 1, 5, 5, 8, 20] and key 5, you should return the index 3. Your solution should be a binary search, that is, it should run in O(log n) t…
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| public class Search{ | |
| private int binarySearch(int arr[], int key){ | |
| if(arr == null) | |
| throw new RuntimeException("Null array found"); | |
| int l = 0; // lower limit | |
| int h = arr.length - 1; // upper limit | |
| int m; | |
| while(l <= h){ | |
| m = l + (h-l)/2; | |
| if(arr[m] == key) | |
| return m; | |
| else if(arr[m] > key) | |
| h = m - 1; | |
| else | |
| l = m + 1; | |
| } | |
| return -1; | |
| } | |
| public static void main(String args[]){ | |
| Search search = new Search(); | |
| System.out.println("Key index is : " + search.binarySearch(new int[]{-10,-2,1,5,5,8,20},5)); | |
| } | |
| } |
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