week16- A1. Apple Pen Easy, Author Solution

#include<bits/stdc++.h>
using namespace std;
const int SIZE = 101;
string s[SIZE],T;
int main(){
    ios_base::sync_with_stdio(false);
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)cin>>s[i];
    cin>>T;
    vector<pair<int,int> >an;
    for(int i=1;i<=n;i++)
        for(int j=i+1;j<=n;j++){
            if(s[i]+s[j]==T||s[j]+s[i]==T)an.push_back(make_pair(i,j));
        }
    printf("%d\n",(int)an.size());
    for(int i=0;i<an.size();i++)printf("%d %d\n",an[i].first,an[i].second);
}