Leetcode刷题笔记(c++)

class Solution {
public:
    vector twoSum(vector& nums, int target) {
        int n=nums.size();
        int pre=0,back=n-1;
        vector out;
        while(pre
            if(nums[pre]+nums[back]>target){
                back--;
            }else if(nums[pre]+nums[back]
                pre++;
            }else{
                out.push_back(nums[pre]);
                out.push_back(nums[back]);
                break;
            }
        }
        return out;
    }
};

class Solution {
public:
    vector twoSum(vector& nums, int target) {
        unordered_sethashset;
        vector out;
        for(int n:nums){
            auto it=hashset.find(target-n);
            if(it!=hashset.end()){
                out.push_back(target-n);
                out.push_back(n);
                break;
            }else{
                hashset.insert(n);
            }
        }
        return out;
    }
};