Description

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

Example:

Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,

return [0, 1].

Solution

class Solution {
public:
vector<int> twoSum(vector<int>& nums, int target) {
    vector<int> result;
    int i = 0;
    int j = 0;
    for (; i < nums.size(); ++i)
    {
      for (j = i+1; j < nums.size(); ++j)
      {
          if ((nums[i] + nums[j]) == target)
          {
              result.push_back(i);
              result.push_back(j);            
              break;
          }
      }
  }

  return result;
}
};

汇总

现在性能一般，有时间在优化吧。