SecondMinMax.java

packagecom.thealgorithms.maths;

importjava.util.function.BiPredicate;

publicfinalclassSecondMinMax {

/**
 * Utility class for finding second maximum or minimum based on BiPredicate
 * @exception IllegalArgumentException => if input array is of length less than 2 also if all elements are same
 * @return the second minimum / maximum value from the input array
 * @author Bharath Sanjeevi ( https://github.com/BharathSanjeeviT )
 */

privateSecondMinMax() {
 }

privatestaticintsecondBest(finalint[] arr, finalintinitialVal, finalBiPredicate<Integer, Integer> isBetter) {
checkInput(arr);
intbest = initialVal;
intsecBest = initialVal;
for (finalintnum : arr) {
if (isBetter.test(num, best)) {
secBest = best;
best = num;
 } elseif ((isBetter.test(num, secBest)) && (num != best)) {
secBest = num;
 }
 }
checkOutput(secBest, initialVal);
returnsecBest;
 }

/**
 * @brief Finds the Second minimum / maximum value from the array
 * @param arr the input array
 * @exception IllegalArgumentException => if input array is of length less than 2 also if all elements are same
 * @return the second minimum / maximum value from the input array
 * @author Bharath Sanjeevi ( https://github.com/BharathSanjeeviT )
 */

publicstaticintfindSecondMin(finalint[] arr) {
returnsecondBest(arr, Integer.MAX_VALUE, (a, b) -> a < b);
 }

publicstaticintfindSecondMax(finalint[] arr) {
returnsecondBest(arr, Integer.MIN_VALUE, (a, b) -> a > b);
 }

privatestaticvoidcheckInput(finalint[] arr) {
if (arr.length < 2) {
thrownewIllegalArgumentException("Input array must have length of at least two");
 }
 }

privatestaticvoidcheckOutput(finalintsecNum, finalintinitialVal) {
if (secNum == initialVal) {
thrownewIllegalArgumentException("Input array should have at least 2 distinct elements");
 }
 }
}