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: 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] ]
要怎么解决重复是一个问题
万能的sort就起作用了
public class Solution {
public List<List<Integer>> threeSum(int[] nums) {
List<List<Integer>> result = new ArrayList<>();
Arrays.sort(nums);
for (int i = 0; i + 2 < nums.length; i++) {
if (i > 0 && nums[i] == nums[i - 1]) {
continue;
}
int j = i + 1, k = nums.length - 1;
while (j < k) {
if (nums[j] + nums[k] + nums[i] == 0) {
result.add(Arrays.asList(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--;
}
} else if (nums[j] + nums[k] > -nums[i]) {
k--;
} else {
j++;
}
}
}
return result;
}
}