Sets-STL in C++ HackerRank Solution
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().
Coming to the problem, you will be given queries. Each query is of one of the following three types:
1x : Add an element x to the set.
2x : Delete an element x from the set. (If the number x is not present in the set, then do nothing).
3x : If the number x is present in the set, then print "Yes"(without quotes) else print "No"(without quotes).
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. Each query consists of two integers y and x where y is the type of the query and x is an integer.
Constraints
1 <= Q <= 10^5
1 <= y <= 3
1 <= x <= 10^9
Output Format
For queries of type 3 print "Yes"(without quotes) if the number x is present in the set and if the number is not present, then print "No"(without quotes).
Each query of type 3 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
Solution
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <set>
#include <algorithm>
using namespace std;
int main() {
/* Enter your code here. Read input from STDIN. Print output to STDOUT */
int Q;
cin >> Q;
set<int> s;
for (int i = 0; i < Q; i++) {
int queryType, queryValue;
cin >> queryType >> queryValue;
if (queryType == 1) {
s.insert(queryValue);
} else if (queryType == 2) {
s.erase(queryValue);
} else if (queryType == 3) {
set<int>::iterator it = s.find(queryValue);
if (it != s.end()) {
cout << "Yes" << endl;
} else {
cout << "No" << endl;
}
}
}
return 0;
}
