map-range.cpp

#include<bits/stdc++.h>
#include<map>
#include<string>
using namespace std;
int main()
{
    map<string,long long int>m;
    int i,x,n,y,j,c=0;
    string a,b;
    cin>>n;
    string str,str2;
    for(i=0;i<n;i++)
    {
        cin>>x;
        if(x==0)
        {
            cin>>str>>y;
            m[str]=y;
            c++;
        }
        else if(x==1)
        {
            cin>>str2;
            cout<<m[str2]<<endl;
        }
        else if (x==2)
        {
            cin>>str;
            m[str]=0;

        }
        else
        {
         cin>>a>>b;
         for(auto it=m.lower_bound(a);it!=m.upper_bound(b);++it)
         {
             cout<<it->first<<" "<<it->second<<endl;
         }


        }

    }
    return 0;

}