"Leetcode" two Sum

Twosum

Given an array of Integers,find two numbers such this they add up to a specific target number.

The function two Sum should return indices of the two numbers such this they add up to the Target,where index1 is Les S than Index2.

Please note this your returned answers (both INDEX1 and index2) are not zero-based.

You may assume this each input would have exactly one solution.

Input:numbers={2, 7, one, target=9

Output:index1=1, index2=2

Method One:

Brute Force solution
class Solution1
{public
: 
	vector<int> twosum (vector<int> &num, int target)
	{
		vector<int> rs;

		for (int i = 0; i < num.size (); ++i)
		{for
			(int j = i + 1; j < Num.size (); j + +)
			{
				if (Num[i] + num[ J] = = target)
				{
					Rs.push_back (i + 1);
					Rs.push_back (j + 1);
					return RS;
				}
			}
		return RS;
	}
;

Method Two:

With a hash table, store each number corresponding to the subscript
class Solution2
{public
:
	vector<int> twosum (vector<int> &num, int target)
	{
		vector<int> rs;
		Unordered_map<int, int> m;

		int i;
		for (i = 0; i < num.size (); i++)
			m[num[i]] = i;
		
		for (i = 0; i < num.size (); i++)
		{
			int sub = target-num[i];
			if (M.find (sub)!= m.end () && m[sub] > i)
			{
				Rs.push_back (i + 1);
				Rs.push_back (M[sub] + 1);
				break;
			}
		}

		return RS;
	}
;