标签：des style color io os java ar strong for
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:
For example, given array S = {-1 0 1 2 -1 -4},
A solution set is:
(-1, 0, 1)
(-1, -1, 2)
public class Solution {
public void swap(int []array,int i,int j){
int t=array[i];
array[i]=array[j];
array[j]=t;
}
public void quickSort(int []array,int start,int end)
{
if(start>=end)
{
return ;
}
int middle=(start+end)/2;
swap(array,start,middle);
int i=start+1;
while(i<=end){
if(array[i]>=array[start]){
break;
}
i++;
}
int j=i+1;
for(;j<=end;){
while(j<=end)
{
if(array[j]<array[start])
{
break;
}
j++;
}
if(j<=end){
swap(array,i,j);
i++;
j++;
}
}
i--;
if(array[i]<array[start]){
swap(array,start,i);
}
quickSort(array,start,i-1);
quickSort(array,i+1,end);
}
List<List<Integer>> twoSum(int []array,int startIndex,int dest)
{
int endIndex=array.length-1;
List<List<Integer>> result=new LinkedList<List<Integer>>();
while(endIndex>startIndex)
{
int sum=array[startIndex]+array[endIndex];
if(sum==dest)
{
List <Integer>p=new LinkedList<Integer>();
p.add(array[startIndex]);
p.add(array[endIndex]);
result.add(p);
for(startIndex++;startIndex<=endIndex;startIndex++)
{
if(array[startIndex]!=array[startIndex-1])
{
break;
}
}
}
if(sum>dest)
{
endIndex--;
}
if(sum<dest){
startIndex++;
}
}
return result;
}
public List<List<Integer>> threeSum(int[] num) {
List<List<Integer>> result=new LinkedList<List<Integer>>();
if(num==null||num.length<3)
{
return result;
}
int []array=new int[num.length];
for(int i=0;i<num.length;i++)
{
array[i]=num[i];
}
quickSort(array,0,array.length-1);
for(int i=0;i+2<array.length;){
List<List<Integer>> list=twoSum(array,i+1,0-array[i]);
for(List<Integer>p:list)
{
p.add(0,array[i]);
result.add(p);
}
for(i++;i<array.length;i++){
if(array[i]!=array[i-1])
{
break;
}
}
}
return result;
}
}标签：des style color io os java ar strong for
原文地址：http://blog.csdn.net/jiewuyou/article/details/39250271
