hackerrank>Dashboard>C++>STL>Sets-STL

Sets are a part of the C++ STL. Sets are containers that store unique elements following a specific order. Here are some of the frequently used member functions of sets:

Declaration:

set<int>s; //Creates a set of integers.

Size:

int length=s.size(); //Gives the size of the set.

Insert:

s.insert(x); //Inserts an integer x into the set s.

Erasing an element:

s.erase(val); //Erases an integer val from the set s.

Finding an element:

set<int>::iterator itr=s.find(val); //Gives the iterator to the element val if it is found otherwise returns s.end() .
Ex: set<int>::iterator itr=s.find(100); //If 100 is not present then it==s.end().

To know more about sets
click Here. Coming to the problem, you will be given
queries. Each query is of one of the following three types:

: Add an element

to the set.
: Delete an element

from the set. (If the number
is not present in the set, then do nothing).
: If the number

is present in the set, then print "Yes"(without quotes) else print "No"(without quotes).

Input Format

The first line of the input contains
where
is the number of queries. The next
lines contain
query each. Each query consists of two integers
and
where
is the type of the query and
is an integer.

Constraints

Output Format

For queries of type
print "Yes"(without quotes) if the number
is present in the set and if the number is not present, then print "No"(without quotes).

Each query of type
should be printed in a new line.

Sample Input

8
1 9
1 6
1 10
1 4
3 6
3 14
2 6
3 6

Sample Output

Yes
No
No

1.存入一个数，2.删除一个数，3.查找是否存在某个数

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#define MAX 1e9+8
using namespace std;
int main()
{
int N;
while(~scanf("%d",&N))
{
set<int>myset;
int n,m;
string s[2]={"No","Yes"};
while(N--)
{
cin>>n>>m;
if(n==1)
myset.insert(m);
if(n==2)
myset.erase(m);
if(n==3)
cout<<s[myset.count(m)]<<endl;
}
}
return 0;
}