leetcode 1 Two Sum

最新推荐文章于 2022-02-22 21:10:36 发布

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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].

解：暴力搜索都会，这里用依次遍历的方法，如何快捷的找到所要的数是否在数组中呢，hash是一个不错的选择

代码：

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