-
Notifications
You must be signed in to change notification settings - Fork 1
/
15-3Sum.java
41 lines (34 loc) · 1.27 KB
/
15-3Sum.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
class Solution {
public List<List<Integer>> threeSum(int[] nums) {
List<List<Integer>> result = new ArrayList<List<Integer>>();
//sort the array
Arrays.sort(nums);
for(int i = 0; i < nums.length; i++) {
//skip equal elements to avoid dublicates at i;
if(i - 1 >= 0 && nums[i] == nums[i - 1]) continue;
//two pointers
int left = i + 1;
int right = nums.length - 1;
while(left < right) {
int sum = nums[i] + nums[left] + nums[right];
if(sum == 0) {
//adding to result array
result.add(Arrays.asList(nums[i], nums[left], nums[right]));
//skip dublicates at left pointer
while(left + 1 < right && nums[left] == nums[left + 1])
left++;
//skip dublicates at right pointer
while(right - 1 > left && nums[right] == nums[right - 1])
right--;
left++;
right--;
} else if(sum < 0) {
left++;
} else {
right--;
}
}
}
return result;
}
}