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| 1 | +#include<bits/stdc++.h> |
| 2 | +using namespace std; |
| 3 | + |
| 4 | +// Lets make a function to print map and getting its size |
| 5 | + |
| 6 | +void print(unordered_map<int,string> &m) |
| 7 | +{ |
| 8 | + cout<<"Size of the map is "<<m.size()<<endl; |
| 9 | + for (auto pr :m) |
| 10 | + cout<<pr. first<< " "<<pr. second<< " "<<endl; |
| 11 | +} |
| 12 | + |
| 13 | +int main () |
| 14 | +{ |
| 15 | + // 1. inbuilt impletation : It uses hash table it dont uses trees like map // here keys will make hash value |
| 16 | + // 2. Time complexity : O(1)-> Insertion and access |
| 17 | + // 3. valid keys datatypes : we cant keep all type of data types like pair of pair |
| 18 | + // we can use int double string float ... cz these all have possible hash value |
| 19 | + unordered_map<int,string>m; |
| 20 | + // unordered map does not store in sorted manner it will print randomly |
| 21 | + |
| 22 | + m[8]="Shivendra"; // insertion takes O(1) |
| 23 | + m[3]="abc"; |
| 24 | + m[5]="cdc"; |
| 25 | + m.insert({1,"shiv"}); |
| 26 | + /*map<int,string>:: iterator it; |
| 27 | + for (it=m.begin();it!=m.end();++it) |
| 28 | + { |
| 29 | + cout<<it->first<<" "<<it->second<<" "<<endl; // it will give the sorted output |
| 30 | + }*/ |
| 31 | + /*m.find // O(1) |
| 32 | + m.earese// o(1)*/ |
| 33 | + for (auto &pr :m){ |
| 34 | + cout<<pr. first<< " "<<pr. second<< " "<<endl; |
| 35 | + // this will also work as same like above commented code |
| 36 | + |
| 37 | + } |
| 38 | +} |
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