/******************************************************************************
?*??Compilation:??javac?ThreeSum.java
?*??Execution:????java?ThreeSum?input.txt
?*??Dependencies:?In.java?StdOut.java?Stopwatch.java
?*??Data?files:???https://algs4.cs.princeton.edu/14analysis/1Kints.txt
?*????????????????https://algs4.cs.princeton.edu/14analysis/2Kints.txt
?*????????????????https://algs4.cs.princeton.edu/14analysis/4Kints.txt
?*????????????????https://algs4.cs.princeton.edu/14analysis/8Kints.txt
?*????????????????https://algs4.cs.princeton.edu/14analysis/16Kints.txt
?*????????????????https://algs4.cs.princeton.edu/14analysis/32Kints.txt
?*????????????????https://algs4.cs.princeton.edu/14analysis/1Mints.txt
?*
?*??A?program?with?cubic?running?time.?Reads?n?integers
?*??and?counts?the?number?of?triples?that?sum?to?exactly?0
?*??（ignoring?integer?overflow）.
?*
?*??%?java?ThreeSum?1Kints.txt?
?*??70
?*
?*??%?java?ThreeSum?2Kints.txt?
?*??528
?*
?*??%?java?ThreeSum?4Kints.txt?
?*??4039
?*
?******************************************************************************/

package?edu.princeton.cs.algs4;

/**
?*??The?{@code?ThreeSum}?class?provides?static?methods?for?counting
?*??and?printing?the?number?of?triples?in?an?array?of?integers?that?sum?to?0
?*??（ignoring?integer?overflow）.
?*??

?*??This?implementation?uses?a?triply?nested?loop?and?takes?proportional?to?n^3
?*??where?n?is?the?number?of?integers.
?*??

?*??For?additional?documentation?see?Section?1.4?of
?*??Algorithms?4th?Edition?by?Robert?Sedgewick?and?Kevin?Wayne.
?*
?*??@author?Robert?Sedgewick
?*??@author?Kevin?Wayne
?*/
public?class?ThreeSum?{

????//?Do?not?instantiate.
????private?ThreeSum（）?{?}

????/**
?????*?Prints?to?standard?output?the?（i?j?k）?with?{@code?i??????*?such?that?{@code?a[i]?+?a[j]?+?a[k]?==?0}.
?????*
?????*?@param?a?the?array?of?integers
?????*/
????public?static?void?printAll（int[]?a）?{
????????int?n?=?a.length;
????????for?（int?i?=?0;?i?????????????for?（int?j?=?i+1;?j?????????????????for?（int?k?=?j+1;?k?????????????????????if?（a[i]?+?a[j]?+?a[k]?==?0）?{
????????????????????????StdOut.println（a[i]?+?“?“?+?a[j]?+?“?“?+?a[k]）;
????????????????????}
????????????????}
????????????}
????????}
????}?

????/**
?????*?Returns?the?numb