Given an array nums
of n integers, are there elements a, b, c in nums
such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.
Note:
The solution set must not contain duplicate triplets.
Example:
Given array nums = [-1, 0, 1, 2, -1, -4], A solution set is: [ [-1, 0, 1], [-1, -1, 2] ]
import java.util.ArrayList;
import java.util.List;
import java.util.Arrays;
class num15{
public List<List<Integer>> threeSum(int[] nums) {
List<List<Integer>> result = new ArrayList<>();
if(nums.length < 3) return result;
Arrays.sort(nums);
int i = 0;
while(i < nums.length - 2) {
if(nums[i] > 0) break;
int j = i + 1;
int k = nums.length - 1;
while(j < k) {
int sum = nums[i] + nums[j] + nums[k];
if(sum == 0) result.add(Arrays.asList(nums[i], nums[j], nums[k]));
if(sum <= 0) while(nums[j] == nums[++j] && j < k);
if(sum >= 0) while(nums[k--] == nums[k] && j < k);
}
while(nums[i] == nums[++i] && i < nums.length - 2);
}
return result;
}
public static void main(String[] args) {
num15 s = new num15();
int[] array = new int[]{-1, 0, 1, 2, -1, -4};
System.out.println(s.threeSum(array));
}
}