LeetCode Two Sum, leetcodetwosum
Given an array of integers, find two numbers such that they add up to a specific target number.
The function twoSum shocould 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 wowould have exactly one solution.
Input: numbers = {2, 7, 11, 15}, target = 9
Output: index1 = 1, index2 = 2
Question: Here is an array that tells you that the unique solution is that the sum of the two numbers equals to the target, and the subscript is
Idea: map discrete storage, a relatively simple question
class Solution {public: vector<int> twoSum(vector<int> &numbers, int target) { vector<int> ans; map<int, int> mp; for (int i = 0; i < numbers.size(); i++) { int tmp = target - numbers[i]; if (mp.find(tmp) != mp.end()) { ans.push_back(mp[tmp]); ans.push_back(i+1); } else mp[numbers[i]] = i+1; } return ans; }};