LeetCode Two Sum

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fox64194167 2022-08-01 17:28:04 ©著作权

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1.题目

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

2.解决方案之一

typedef struct node{
    int originalIndex;
    int val;
    node(){};
    node(int index, int v):originalIndex(index),val(v){}
} Node;

bool compare(const Node& a, const Node& b){
    return a.val < b.val;
}
class Solution {
public:
    


    vector<int> twoSum(vector<int> &numbers, int target) {
       vector<int> result;

    int length = numbers.size();

    vector<Node> nums(length);
    for(int i = 0; i < numbers.size(); ++i){
        nums[i] = Node(i, numbers[i]);
    }

    sort(nums.begin(), nums.end(), compare);

    int left = 0;
    int right = length - 1;

    while(left < right){
        int sum = nums[left].val + nums[right].val;
        if(sum == target){
            result.push_back(min(nums[left].originalIndex + 1, nums[right].originalIndex + 1));
            result.push_back(max(nums[left].originalIndex + 1, nums[right].originalIndex + 1));
            break;
        }else if(sum < target){
            left++;
        }else{
            right--;
        }
    }
    return result;
    }
};