package com.thealgorithms.searches;
import com.thealgorithms.devutils.searches.SearchAlgorithm;
/**
* An iterative implementation of the Ternary Search algorithm.
*
* <p>
* Ternary search is a divide-and-conquer algorithm that splits the array into three parts
* instead of two, as in binary search. This implementation is iterative, reducing the overhead
* associated with recursive function calls. However, the recursive version can also be optimized
* by the Java compiler to resemble the iterative version, resulting in similar performance.
*
* <p>
* Worst-case performance: Θ(log3(N))<br>
* Best-case performance: O(1)<br>
* Average performance: Θ(log3(N))<br>
* Worst-case space complexity: O(1)
*
* <p>
* This class implements the {@link SearchAlgorithm} interface, providing a generic search method
* for any comparable type.
*
* @see SearchAlgorithm
* @see TernarySearch
* @since 2018-04-13
*/
public class IterativeTernarySearch implements SearchAlgorithm {
@Override
public <T extends Comparable<T>> int find(T[] array, T key) {
if (array == null || array.length == 0 || key == null) {
return -1;
}
if (array.length == 1) {
return array[0].compareTo(key) == 0 ? 0 : -1;
}
int left = 0;
int right = array.length - 1;
while (right > left) {
int leftCmp = array[left].compareTo(key);
int rightCmp = array[right].compareTo(key);
if (leftCmp == 0) {
return left;
}
if (rightCmp == 0) {
return right;
}
int leftThird = left + (right - left) / 3 + 1;
int rightThird = right - (right - left) / 3 - 1;
if (array[leftThird].compareTo(key) <= 0) {
left = leftThird;
} else {
right = rightThird;
}
}
return -1;
}
}