LeetCode学习_Two Sum

最新推荐文章于 2020-12-09 23:11:04 发布

SBC_19

最新推荐文章于 2020-12-09 23:11:04 发布

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本文介绍了一个算法，用于在给定的整数数组中找到两个数，它们的和等于特定的目标数。通过使用哈希映射，该算法能够高效地找到满足条件的数对，并返回它们在数组中的非零基索引。

Two Sum

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

class Solution
{
public:
vector<int> twoSum(vector<int>& nums, int target)
{
vector<int> result;
unordered_map<int, int> mapping;
for (int i = 0; i < nums.size(); i ++)
{
mapping[nums[i]] = i;
}
for (int i = 0; i < nums.size(); i ++)
{
const int gap = target - nums[i];
if (mapping.find(gap) != mapping.end() && mapping[gap] > i)
{
result.push_back(i + 1);
result.push_back(mapping[gap] + 1);
break;
}
}
return result;
}
};