|
| 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(map<int,string> &m) |
| 7 | +{ |
| 8 | + cout<<"Size of the map is "<<m.size()<<endl; |
| 9 | + for (auto pr :m) // this loop is of O(n) |
| 10 | + cout<<pr. first<< " "<<pr. second<< " "<<endl; // O(nlogn) |
| 11 | +} |
| 12 | +// map uses red black self balencing tree in backend and it always stored keys in sorted manner |
| 13 | +int main () |
| 14 | +{ |
| 15 | + map<int,string>m; |
| 16 | + // map can store any kind of data types even set, vector .. |
| 17 | + // all the keys of map will always be unique |
| 18 | + // map stores keys & values in sorted order |
| 19 | + // if we keep string then it will be stored in lexographical order |
| 20 | + |
| 21 | + m[8]="Shivendra"; // insertion takes O(logn) |
| 22 | + m[3]="abc"; // O(logm) |
| 23 | + m[5]="cdc"; // when we wrote this even after there is no value it will take any value by it self |
| 24 | + m.insert({1,"shiv"}); |
| 25 | + // when you want to directly access some specific value in map using m[key] or m.find(key), these are log(n) operations as log(n)time is taken by map to search this key. |
| 26 | + m.erase(3); // O(log(n)) |
| 27 | + auto it = m.find(3); // O(long(n)) |
| 28 | + m.erase(it); // O(log(n)) // it will delete the key 3 and value |
| 29 | + m.clear(); // it will clear(delete) full map |
| 30 | + if (it== m.end()) |
| 31 | + cout<<"NO Value "; |
| 32 | + else |
| 33 | + cout <<it->first <<" "<<it->second <<" "<<endl; |
| 34 | + /*print(m);*/ |
| 35 | + print(m); |
| 36 | +} |
| 37 | +// |
0 commit comments