LeetCode --> 1.Two Sum

Two Sum

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].

 

 

 

 

 

 

代码：

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        unordered_map<int, int> hash;
        vector<int> res;
        
        for(int i = 0; i < nums.size(); i++) {
            int diff = target - nums[i];
            if(hash.find(diff) != hash.end()) {
                res.push_back(hash[diff]);
                res.push_back(i);
                return res;
            }
            hash[nums[i]] = i;
        }
        
        return res;
    }
};

 地址： https://leetcode.com/submissions/detail/142137584/