twosum(new edition)

//最优方法 map查找法,map的查询时间复杂度为LogN
#include<iostream>
#include<vector>
#include<map>
#include<unordered_map>//unordered_map的映射表是不会对键进行排序的，是按照存进去的顺序放置的，但是map创建的映射表则是会对键值进行排序的。
using namespace std;
class solution{
public:
vector<int> twosum(vector<int>&num, int& target)
{
map<int, int> hash;
map<int, int>::const_iterator iter;
map<int, int>::const_iterator iterend;
vector<int> result;
for (int i = 0; i < int(num.size()); i++)
{
int numtofind = target - num[i];
iter = hash.find(numtofind);
iterend = hash.end();
if (hash.find(numtofind) != hash.end())//由键索引值,键存的是数组值，值存的是数组索引
{
result.push_back(hash[numtofind]);
result.push_back(i);
}
else
{
hash[num[i]] = i;
}
}
return result;
}
};
int main()
{
vector<int> nums = {3,4,1,2,3,1};
int target = 2;
solution s;
vector<int> result;
result=s.twosum(nums, target);
cout << result[0] << ' ' << result[1] << endl;
}