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3Sum

Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.

Note:

• Elements in a triplet (a,b,c) must be in non-descending order. (ie, a ≤ b ≤ c)
• The solution set must not contain duplicate triplets.

For example, given array S = {-1 0 1 2 -1 -4},    A solution set is:    (-1, 0, 1)    (-1, -1, 2)

public class Solution {    public List
   
    
     > threeSum(int[] num) {       if (num == null) return null;    List
     
      
       > result = new ArrayList
       
        
         >(); int len = num.length; // Sort Arrays.sort(num); for (int i=0; i
         
           l = new ArrayList
          
           (); l.add(num[i]); l.add(num[j]); l.add(num[k]); result.add(l); // Bypass second and third elements int K = k; while (k
          
         
        
       
      
     
    
   

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