95 lines
2.6 KiB
Java
95 lines
2.6 KiB
Java
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//给你一个包含 n 个整数的数组 nums，判断 nums 中是否存在三个元素 a，b，c ，使得 a + b + c = 0 ？请你找出所有和为 0 且不重
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//复的三元组。
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//
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// 注意：答案中不可以包含重复的三元组。
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//
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//
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//
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// 示例 1：
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//
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//
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//输入：nums = [-1,0,1,2,-1,-4]
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//输出：[[-1,-1,2],[-1,0,1]]
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//
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//
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// 示例 2：
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//
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//
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//输入：nums = []
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//输出：[]
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//
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//
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// 示例 3：
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//
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//
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//输入：nums = [0]
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//输出：[]
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//
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//
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//
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//
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// 提示：
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//
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//
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// 0 <= nums.length <= 3000
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// -105 <= nums[i] <= 105
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//
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// Related Topics 数组 双指针
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// 👍 3303 👎 0
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package leetcode.editor.cn;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collections;
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import java.util.List;
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import java.util.stream.Collectors;
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//15:三数之和
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public class ThreeSum {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new ThreeSum().new Solution();
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// solution.threeSum(new int[]{-1, 0, 1, 2, -1, -4});
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// solution.threeSum(new int[]{-4, -2, -2, -2, 0, 1, 2, 2, 2, 3, 3, 4, 4, 6, 6});
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solution.threeSum(new int[]{-4, -2, -1});
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class Solution {
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public List<List<Integer>> threeSum(int[] nums) {
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int n = nums.length;
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Arrays.sort(nums);
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List<List<Integer>> ans = new ArrayList<List<Integer>>();
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for (int first = 0; first < n; ++first) {
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if (first > 0 && nums[first] == nums[first - 1]) {
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continue;
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}
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int third = n - 1;
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int target = -nums[first];
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for (int second = first + 1; second < n; ++second) {
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if (second > first + 1 && nums[second] == nums[second - 1]) {
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continue;
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}
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while (second < third && nums[second] + nums[third] > target) {
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--third;
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}
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if (second == third) {
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break;
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}
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if (nums[second] + nums[third] == target) {
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List<Integer> list = new ArrayList<Integer>();
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list.add(nums[first]);
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list.add(nums[second]);
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list.add(nums[third]);
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ans.add(list);
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}
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}
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}
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return ans;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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}
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