[Face question] Find 3 numbers in the array so that they are 0

Given an array of s, try to find 3 numbers A, B, C, making a+b+c=0. That is to find out all the 0 and 3 numbers from the collection. For example: Set s={-1,0, 1, 2,-1, 4}, the 3-digit number that satisfies the condition has 2 pairs: (-1, 0, 1) and ( -1, 2,-1)。 Note ( -1,1,0) that the same solution is calculated with ( -1,0,1), so there is no need to think again. The solution of this example collection can also be written as: (0, 1,-1) and (2,-1,-1)。 Reference: http://blog.csdn.net/wangran51/article/details/8858398, he gave the code a little bit of a problem. overriding algorithms using Java code

1  Packagecom.sum3;2 3 Importjava.util.ArrayList;4 Importjava.util.Collections;5 ImportJava.util.HashSet;6 Importjava.util.List;7 ImportJava.util.Set;8 9  Public classSum3 {Ten  One     Private StaticSet<list<integer>> fing_sum3 (list<integer>arr) { ACollections.sort (arr);//sort an array first -          for(Integer ainteger:arr) { - System.out.println (Ainteger); the         } -List<integer>List3; -Set<list<integer>> setlist =NewHashset<>(); -          +          for(inti = 0; I < Arr.size ()-2; i++){ -             intj = i+1; +             intK = Arr.size ()-1; A              while(J <k) { at                 //fixed arr[i] does not move, the left and right approximation; arr[j] too small, move forward one -                 if(Arr.get (i) + Arr.get (j) + Arr.get (k) < 0 ) { -J + +; -}Else if(Arr.get (i) + Arr.get (j) + Arr.get (k) > 0){ -k--; -}Else { inList3 =NewArraylist<>(); - List3.add (Arr.get (i)); to List3.add (Arr.get (j)); + List3.add (Arr.get (k)); - Setlist.add (LIST3); the                     //j++;//This needs to be erased, otherwise some elements are not counted. *k--; $                 }Panax Notoginseng             } -         } the         returnsetlist; +     } A      the      +      Public Static voidMain (string[] args) { -Integer[] List = {2,1,0,-1,1,4,2,-2,-3}; $Arraylist<integer> ArrayList =NewArraylist<>(list.length); $ Collections.addall (arrayList, list); -set<list<integer>> output =fing_sum3 (arrayList); -          for(list<integer>list2:output) { the System.out.println (list2); -         }Wuyi     } the  -}

Output Result:

-3-2-1 0 1 1 2 2 4

[-3,-1, 4]
[-3, 1, 2]
[-2, 1, 1]
[-2, 0, 2]
[-1, 0, 1]

[Face question] Find 3 numbers in the array so that they are 0