# ThreeSumDeluxe.java

Below is the syntax highlighted version of ThreeSumDeluxe.java from §4.2 Sorting and Searching.

```/******************************************************************************
*  Compilation:  javac ThreeSumDeluxe.java
*  Execution:    java ThreeSumDeluxe < input.txt
*
*  A program with n^2 log n running time. Read in n integers
*  and counts the number of triples that sum to exactly 0.
*
*  Limitations
*  -----------
*     - we ignore integer overflow
*     - doesn't handle case when input has duplicates
*
******************************************************************************/

import java.util.Arrays;

public class ThreeSumDeluxe {

// print distinct triples (i, j, k) such that a[i] + a[j] + a[k] = 0
public static void printAll(int[] a) {
int n = a.length;
Arrays.sort(a);
for (int i = 0; i < n; i++) {
for (int j = i+1; j < n; j++) {
int k = Arrays.binarySearch(a, -(a[i] + a[j]));
if (k >= 0 && k > j) {
StdOut.println(a[i] + " " + a[j] + " " + a[k]);
}
}
}
}

// return number of distinct triples (i, j, k) such that a[i] + a[j] + a[k] = 0
public static int count(int[] a) {
int n = a.length;
Arrays.sort(a);
int count = 0;
for (int i = 0; i < n; i++) {
for (int j = i+1; j < n; j++) {
int k = Arrays.binarySearch(a, -(a[i] + a[j]));
if (k >= 0 && k > j) {
count++;
}
}
}
return count;
}

public static void main(String[] args)  {
int[] a = StdIn.readAllInts();
int n = a.length;
int count = count(a);
StdOut.println(count);
if (count < 100) {
printAll(a);
}
}
}
```

Copyright © 2000–2022, Robert Sedgewick and Kevin Wayne.
Last updated: Thu Aug 11 10:29:15 EDT 2022.