Algorithm
Problem Name:
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.
Constraints
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
7
1 Jesse 20
1 Jess 12
1 Jess 18
3 Jess
3 Jesse
2 Jess
3 Jess
Sample Output
30
20
0
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;
switch(t)
{
case 1:
cin >> val;
m[s] += val;
break;
case 2:
m.erase(s);
break;
case 3:
it = m.find(s);
cout << (it != m.end() ? ((*it).second) : 0) << endl;
}
}
return 0;
}
Input
Output