LeetCode:Tow Sum程序以及分析

URL: https://leetcode.com/problems/two-sum/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].           

Code:

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        map<int,int> array;
        vector<int> result;

        for(int i = 0;i < nums.size(); i ++)
        {
            array[nums[i]] = i;
        }
        for(int i = 0;i < nums.size(); i ++)
        {
            result.push_back(i);
            int dif = target - nums[i];
            if(array.find(dif) != array.end() && i != array[dif])
            {
                result.push_back(array[dif]);
                return result;
            }   
            else
                result.pop_back();

        }
    }
};