60 lines
1.4 KiB
Java
60 lines
1.4 KiB
Java
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import java.util.Arrays;
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import java.util.Random;
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/**
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*
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* @author Gabriele La Greca : https://github.com/thegabriele97
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*
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*/
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public final class IterativeBinarySearch {
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/**
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* This method implements an iterative version of binary search algorithm
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*
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* @param array a sorted array
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* @param key the key to search in array
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*
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* @return the index of key in the array or -1 if not found
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*/
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public static <T extends Comparable<T>> int binarySearch(T[] array, T key) {
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int l, r, k, cmp;
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l = 0;
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r = array.length - 1;
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while (l <= r) {
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k = (l + r) / 2;
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cmp = key.compareTo(array[k]);
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if (cmp == 0) {
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return k;
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} else if (cmp < 0) {
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r = --k;
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} else if (cmp > 0) {
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l = ++k;
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}
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}
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return -1;
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}
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//Only a main method for test purpose
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public static void main(String[] args) {
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Random rand = new Random();
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int base = rand.nextInt(1000);
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Integer[] array = new Integer[65535];
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for (int i = 0; i < array.length; i++) {
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array[i] = base + (i + 1);
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}
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//Arrays.sort(array); //if needed
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Integer key = base + rand.nextInt(array.length * 2); //can generate keys that aren't in array
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System.out.println(binarySearch(array, key));
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System.out.println(Arrays.binarySearch(array, key));
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}
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}
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