algorithm/Java
1
0
Fork 0
mirror of https://github.com/TheAlgorithms/Java.git synced 2025-07-06 17:29:31 +08:00
Code Issues Packages Projects Releases Wiki Activity

refactor: TwoPointers (#5380)

Browse Source
This commit is contained in:
Alex Klymenko
2024-08-25 08:29:17 +02:00
committed by GitHub
parent b231a72d44
commit 38688440ef
2 changed files with 50 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
src/main/java/com/thealgorithms/others/TwoPointers.java
View File

@ -1,39 +1,33 @@
package com.thealgorithms.others;
import java.util.Arrays;
/**
* The two pointer technique is a useful tool to utilize when searching for
* The two-pointer technique is a useful tool to utilize when searching for
* pairs in a sorted array.
*
* <p>
* link: https://www.geeksforgeeks.org/two-pointers-technique/
* Link: https://www.geeksforgeeks.org/two-pointers-technique/
*/
final class TwoPointers {
private TwoPointers() {
}
/**
* Given a sorted array arr (sorted in ascending order). Find if there
* exists any pair of elements such that their sum is equal to key.
* Given a sorted array arr (sorted in ascending order), find if there exists
* any pair of elements such that their sum is equal to the key.
*
* @param arr the array contains elements
* @param arr the array containing elements (must be sorted in ascending order)
* @param key the number to search
* @return {@code true} if there exists a pair of elements, {@code false}
* otherwise.
* @return {@code true} if there exists a pair of elements, {@code false} otherwise.
*/
public static boolean isPairedSum(int[] arr, int key) {
/* array sorting is necessary for this algorithm to function correctly */
Arrays.sort(arr);
int i = 0;
/* index of first element */
int j = arr.length - 1;
/* index of last element */
int i = 0; // index of the first element
int j = arr.length - 1; // index of the last element
while (i < j) {
if (arr[i] + arr[j] == key) {
int sum = arr[i] + arr[j];
if (sum == key) {
return true;
} else if (arr[i] + arr[j] < key) {
} else if (sum < key) {
i++;
} else {
j--;