-
Notifications
You must be signed in to change notification settings - Fork 0
/
15. 三数之和.java
40 lines (40 loc) · 1.23 KB
/
15. 三数之和.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
class Solution {
public List<List<Integer>> threeSum(int[] nums) {
List<List<Integer>> result = new ArrayList<>();
int len = nums.length;
if (nums == null || len < 3) {
return result;
}
Arrays.sort(nums);
for (int i = 0; i < len - 2; i++) {
if (nums[i] > 0) {// 三数之和一定大于0,所以结束循环
break;
}
if (i > 0 && nums[i] == nums[i - 1]) {// 去重
continue;
}
int L = i + 1;
int R = len - 1;
while (L < R) {
int sum = nums[i] + nums[L] + nums[R];
if (sum == 0) {
result.add(Arrays.asList(nums[i], nums[L], nums[R]));
// 去重
while (L < R && nums[L] == nums[L + 1]) {
L++;
}
while (L < R && nums[R] == nums[R - 1]) {
R--;
}
L++;
R--;
} else if (sum > 0) {
R--;
} else {
L++;
}
}
}
return result;
}
}