Two Sum

最新推荐文章于 2024-08-26 10:01:55 发布

Clearle

最新推荐文章于 2024-08-26 10:01:55 发布

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分类专栏： LeetCode

本文链接：https://blog.youkuaiyun.com/budlele/article/details/40477493

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本文介绍了一种解决两数之和问题的有效算法。给定一个整数数组及目标值，寻找两个数相加等于该目标值的下标。通过使用map边找边存的方法，确保了快速匹配并返回正确答案。

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Given an array of integers, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2. Please note that your returned answers (both index1 and index2) are not zero-based.

You may assume that each input would have exactly one solution.

Input: numbers={2, 7, 11, 15}, target=9

Output: index1=1, index2=2

用map边找边存，还是挺简单的。。输出要有序

class Solution {
public:
    vector<int> twoSum(vector<int> &numbers, int target) {
        map<int ,int> p; p.clear();
        vector<int> ans;
        for(int i=0;i<numbers.size();i++){
            if(p.find(target-numbers[i])!=p.end()){
                ans.push_back(p[target-numbers[i]]+1);
                ans.push_back(i+1);
            }
            else p[numbers[i]]=i;
        }
        return ans;


    }
};