Problem Name: Maps-STL

Problem Link:

In this HackerRank Functions in C++ programming problem solution,

Maps are a part of the C++ STL.Maps are associative containers that store elements formed by a combination of a key value and a mapped value, following a specific order.The mainly used member functions of maps are:


  • Map Template:

    std::map <key_type, data_type>
  • Declaration:

    map<string,int>m; //Creates a map m where key_type is of type string and data_type is of type int.
  • Size:

    int length=m.size(); //Gives the size of the map.
  • Insert:

    m.insert(make_pair("hello",9)); //Here the pair is inserted into the map where the key is "hello" and the value associated with it is 9.
  • Erasing an element:

    m.erase(val); //Erases the pair from the map where the key_type is val.
  • Finding an element:

    map<string,int>::iterator itr=m.find(val); //Gives the iterator to the element val if it is found otherwise returns m.end() .
    Ex: map<string,int>::iterator itr=m.find("Maps"); //If Maps is not present as the key value then itr==m.end().
  • Accessing the value stored in the key:

    To get the value stored of the key "MAPS" we can do m["MAPS"] or we can get the iterator using the find function and then by itr->second we can access the value.


To know more about maps click Here.

You are appointed as the assistant to a teacher in a school and she is correcting the answer sheets of the students.Each student can have multiple answer sheets.So the teacher has Q queries:

1 X Y :Add the marks Y to the student whose name is X.

2 X: Erase the marks of the students whose name is X.

3 X: Print the marks of the students whose name is X. (If X didn't get any marks print 0.)

Input Format

The first line of the input contains Q where Q is the number of queries. The next Q lines contain 1 query each.The first integer, type f each query is the type of the query.If query is of type 1, it consists of one string and an integer X and y where X is the name of the student and Y is the marks of the student.If query is of type 2 or 3 ,it consists of a single string X where X s the name of the student.


1 <= Q <= 10**5

1 <= type <= 3

1 <= |X|<= 6

1 <= Y <= 10**3

Output Format

For queries of type 3 print the marks of the given student.

Sample Input

1 Jesse 20
1 Jess 12
1 Jess 18
3 Jess
3 Jesse
2 Jess
3 Jess

Sample Output








Code Examples

#1 Code Example with C++ Programming

Code - C++ Programming

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <set>
#include <map>
#include <algorithm>
using namespace std;

int main()
    int T;
    cin >> T;

    string s;
    map < string, int> m;
    map::iterator it;

    for(int i = 1, t; i  < = T; i++){
        cin >> t >> s;
        int val;
            case 1:
                cin >> val;
                m[s] += val;
            case 2:
            case 3:
                it = m.find(s);
                cout << (it != m.end() ? ((*it).second) : 0) << endl;

    return 0;
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7 1 Jesse 20 1 Jess 12 1 Jess 18 3 Jess 3 Jesse 2 Jess 3 Jess


30 20 0


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