Leetcode Week2 Two Sum

Question

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].

Answer

　　思路: 集合中每两个元素相加与target比较一次即可。

　　

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