package src.leetcode;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.concurrent.CountDownLatch;

public class WaterArea {

public static void main(String[] args) {

int[] arr = {-1,0,1,2,-1,-4};

//int[] arr = {1};

List<List<Integer>> lists = new WaterArea().threeSum(arr);

System.out.println(lists);

}

public List<List<Integer>> threeSum(int[] nums) {

List<List<Integer>> ans = new ArrayList();

int len = nums.length;

Arrays.sort(nums);

for (int i = 0; i < nums.length; i++) {

if(nums[i]>0) break;//i之后的都是大于0的 和不可能大于0

if(i>0 && nums[i]==nums[i-1]){

continue;

}

int L=i+1;

int R=len-1;

while (L< R){

int sum=nums[i]+nums[L]+nums[R];

if (sum==0){

ans.add(Arrays.asList(nums[i],nums[L],nums[R]));

//重复的的 不算 a即 arr[3]==arr[4]时 数值是一个 就用arr[3]的值 就行了

while (L< R && nums[L]==nums[L+1]) L++;

while (L< R && nums[R]==nums[R-1]) R--;

//为什么有++ --

L++;

R--;

}else if (sum >0) {

R--;

}else {

L++;

}

}

}

CountDownLatch cdl = new CountDownLatch(8);

// -- thread

cdl.countDown();

//最后

try {

cdl.await();

} catch (InterruptedException e) {

e.printStackTrace();

}

return ans;

}

}