难度:Medium
解题思路：可以按照3Sum的思路来。代码如下。
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
41
|
class Solution {
public:
vector<vector<int>> fourSum(vector<int>& nums, int target) {
vector<vector<int>> ret;
if(nums.size()<4) return ret;
sort(nums.begin(),nums.end());
for(int i = 0; i < nums.size()-3; i++)
{
if(i!=0 && nums[i]==nums[i-1]) continue;
for(int j = i+1; j < nums.size()-2; j++)
{
if(j!=i+1 && nums[j]==nums[j-1]) continue;
int low = j+1;
int high = nums.size()-1;
while(low < high)
{
if(low != j+1 && nums[low]==nums[low-1])
{
low++;
continue;
}
if(high != nums.size()-1 && nums[high]==nums[high+1]){
high--;
continue;
}
int sum = nums[i]+nums[j]+nums[low]+nums[high];
if(sum == target)
{
ret.push_back({nums[i],nums[j],nums[low],nums[high]});
high--;
}
else if(sum > target)
high--;
else
low++;
}
}
}
return ret;
}
};
|
近期评论