-
Notifications
You must be signed in to change notification settings - Fork 0
/
3sum.java
36 lines (34 loc) · 1.16 KB
/
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
package java;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
class ThreeSum {
List<List<Integer>> ans = new ArrayList<>();
public List<List<Integer>> threeSum(int[] nums) {
if (nums == null || nums.length < 3) return ans;
int len = nums.length;
Arrays.sort(nums);
for (int i = 0; i < len - 2; i++) {
if (nums[i] > 0) return ans;
if (i > 0 && nums[i] == nums[i - 1]) continue;
int j = i + 1, k = len - 1;
while (j < k) {
int sum = nums[i] + nums[j] + nums[k];
if (sum > 0) {
k--;
while (j < k && nums[k] == nums[k + 1]) k--;
} else if (sum < 0) {
j++;
while (j < k && nums[j] == nums[j - 1]) j++;
} else {
ans.add(List.of(nums[i], nums[j], nums[k]));
j++;
k--;
while (j < k && nums[j] == nums[j - 1]) j++;
while (j < k && nums[k] == nums[k + 1]) k--;
}
}
}
return ans;
}
}