LeetCode 1. Two Sum

https://leetcode.com/problems/two-sum/

先排序，有序后枚举a，二分查找b，因为必然有解，直接找到就return。

class Solution {
public:
    struct node
    {
        int num;
        int ord;
    };
    static bool cmp(node a,node b)
        {
            return a.num<b.num;
        }
    int bins(int l,int r,vector<node>& temp,int key)
    {
        while(l<=r)
        {
            int mid=(l+r)>>1;
            if(temp[mid].num==key)
                return mid;
            if(temp[mid].num>key)
                r=mid-1;
            if(temp[mid].num<key)
                l=mid+1;
        }
        return -1;
    }
    vector<int> twoSum(vector<int>& nums, int target) {
        vector<int> ans;
        vector<node> temp;
        for(int i=0;i<nums.size();i++)
            temp.push_back((node){nums[i],i});
        sort(temp.begin(),temp.end(),cmp);
        for(int i=0;i<temp.size();i++)
        {
            int pos=bins(i+1,temp.size()-1,temp,target-temp[i].num);
            if(pos==-1)
                continue;
            else
            {
            ans.push_back(temp[i].ord),ans.push_back(temp[pos].ord);
                return ans;
            }
        }
        return ans;
    }
};