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  1. #include <iostream>
  2. #include <string>
  3. #include <map>
  4. #include <list>
  5.  
  6. using namespace std;
  7.  
  8. int main()
  9. {
  10.     multimap<string,string> students;
  11.     students.insert(make_pair("a","cs1"));
  12.     students.insert(make_pair("b","cs1"));
  13.     students.insert(make_pair("b","cs2"));
  14.     students.insert(make_pair("a","cs2"));
  15.     students.insert(make_pair("c","cs1"));
  16.     students.insert(make_pair("a","cs2"));
  17.     students.insert(make_pair("c","cs2"));
  18.     students.insert(make_pair("c","cs3"));
  19.  
  20.  
  21.     	std::string current_key = "";
  22.         for (auto itr = students.begin(); itr != students.end(); ++itr) 
  23.         { 
  24.             if(current_key == itr->first) {
  25.             	continue;
  26.             } else {
  27.             	current_key = itr->first;
  28.             }
  29.         	const auto result = students.equal_range(itr->first);
  30.         	cout << itr->first << ": ";
  31.         	for(auto it = result.first; it != result.second; ++it) {
  32.         		cout << it->second << " ";
  33.         	}
  34.         	cout << endl;
  35.  
  36.         } 
  37.  
  38. }
Success #stdin #stdout 0s 4452KB
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stdin
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Standard input is empty
stdout
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a: cs1 cs2 cs2 
b: cs1 cs2 
c: cs1 cs2 cs3
https://ideone.com/RqCFOk
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
public

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