[TIOJ] 1302 撿鞋運動…不是，撿鞋問題─強化死筆之路！

LINK：http://tioj.infor.org/problems/1302
　　網路上好像有很多人自己手刻個hash，不過這題應該沒必要(?)，而且我也還不會刻，反正很水，所以就直接用map做了，不過我還是因為忘記打"."而WA了兩次QQ

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
string a,b,c;
unordered_map<string,string> killl,nam;
int main()
{
    ios::sync_with_stdio(0); cin.tie(0);
    while(cin >> a)
    {
        if(a == "add")
        {
            cin >> b >> c;
            nam[b] = c, killl[c] = b;
        }
        else if(a == "chk")
        {
            cin >> b; c = b.substr(1,b.length()-1);
            switch(b[0])
            {
                case 'n':
                    if(nam.find(c) == nam.end()) cout << "Not found." << endl;
                    else cout << c << " " << nam[c] << endl;
                    break;
                default:
                    if(killl.find(c) == killl.end()) cout << "Not found." << endl;
                    else cout << killl[c] << " " << c << endl;
            }
        }
        else 
        {
            cin >> b; c = b.substr(1,b.length()-1);
            switch(b[0])
            {
                case 'n':
                    killl.erase(nam[c]), nam.erase(c);
                    break;
                default:
                    nam.erase(killl[c]), killl.erase(c);
            }
        }
    }
}