Complete program to implement Binary search in java
import static java.lang.String.format;
import java.util.Arrays;
import java.util.Random;
import java.util.concurrent.ThreadLocalRandom;
import java.util.stream.IntStream;
import com.thealgorithms.devutils.searches.SearchAlgorithm;
class BinarySearch implements SearchAlgorithm {
@Override
public <T extends Comparable<T>> int find(T[] array, T key) {
return search(array, key, 0, array.length);
}
private <T extends Comparable<T>> int search(T array[], T key, int left, int right) {
if (right < left) {
return -1; // this means that the key not found
}
// find median
int median = (left + right) >>> 1;
int comp = key.compareTo(array[median]);
if (comp == 0) {
return median;
} else if (comp < 0) {
return search(array, key, left, median - 1);
} else {
return search(array, key, median + 1, right);
}
}
// Driver Program
public static void main(String[] args) {
// Just generate data
Random r = ThreadLocalRandom.current();
int size = 100;
int maxElement = 100000;
Integer[] integers
= IntStream.generate(() -> r.nextInt(maxElement))
.limit(size)
.sorted()
.boxed()
.toArray(Integer[]::new);
// The element that should be found
int shouldBeFound = integers[r.nextInt(size - 1)];
BinarySearch search = new BinarySearch();
int atIndex = search.find(integers, shouldBeFound);
System.out.println(
format(
"Should be found: %d. Found %d at index %d. An array length %d",
shouldBeFound, integers[atIndex], atIndex, size));
int toCheck = Arrays.binarySearch(integers, shouldBeFound);
System.out.println(
format(
"Found by system method at an index: %d. Is equal: %b", toCheck, toCheck == atIndex));
}
}