Leetcode::Two Sum

1.

class Solution {
public:
    vector<int> twoSum(vector<int> &numbers, int target) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
       map<int,int> mp;
       int len = numbers.size();
       
       for( int i=0; i < len; ++i )
       {
           mp[ numbers[ i ] ] = i + 1;
       }
       
       vector<int> result;
       
       for( int i = 0; i < len; ++i )
       {
           map<int,int>::iterator it = mp.find( target - numbers[i] );
           
           if( it != mp.end() )
           {
              result.push_back(it->second);
              result.push_back(i+1);
              sort(result.begin(),result.end());
              break;
           }
       }
       return result;
       
};
};

　　

使用multimap实现；比较笨的方法（map中的键值对是按键排序粗放的）。

class Solution {
public:
    vector<int> twoSum(vector<int> &numbers, int target) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
       multimap<int,int> tmp;
       
       for( int i = 1; i <= numbers.size(); ++i )
       {
           tmp.insert(pair<int,int>(numbers[i-1],i));
       }
       
       multimap<int,int>::iterator index1= tmp.begin();
       multimap<int,int>::iterator index2 = --tmp.end();
       
       while( index1 != index2 )
       {
         int sum = index1->first + index2->first;
         
         if( sum > target )
         --index2;
         else if( sum < target )
         ++index1;
         else
         break;
       }
       
       vector<int> result;
       if(index1->second > index2->second)
       {
           int tmp = index1->second ;
           index1->second =index2->second ;
           index2->second=tmp;
       }
       result.push_back(index1->second);
       result.push_back(index2->second);
       return result;
    }
};