记intel

模拟 inner join：归并的思路

#include<bits/stdc++.h>
using namespace  std;
int main(){
    vector<pair<int,char>> list1 ={{1,'a'},{2,'b'},{2,'c'},{3,'d'}};
    vector<pair<int,char>> list2 ={{1,'e'},{2,'f'},{3,'g'},{4,'h'}};
    int p1=0,p2=0,p3;
    int n1= list1.size(),n2=list2.size();
    int  vis_idx=-1 ;
    vector<tuple<int,char,char>> res;
    while(p1!=n1 and p2!=n2){
        auto tup1=list1[p1],tup2=list2[p2];
        int k1 = tup1.first,k2=tup2.first;
        char v1= tup1.second,v2=tup2.second;
        if(k1==k2){
            res.emplace_back(k1,v1,v2);
            p3 = p1+1;
            while(p3<n1 and list1[p1].first==list1[p3].first){
                res.emplace_back(k1,list1[p3].second,v2);
                vis_idx = p3;
                p3++;
             }
            p2++;
        }else if(k1>k2) {
            p2++;
        }else if(k1<k2){
            p1++;
            while(p1<=vis_idx){
                p1++;
            }
        }
    }

    for(auto p:res){
        std::cout << std::get<0>(p)<<get<1>(p)<<get<2>(p)<<endl;
    }


}