Quiz: STL Algorithms

5 questionsNo time limitPass: 60%+10 XP on first pass

Sort with custom comparators and lambdas, binary search with lower_bound, accumulate, count, reverse, unique, next_permutation, and the fast-I/O setup competitive programmers use.

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Question 1

What does this print?

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main() {
    vector<int> v = {1, 3, 3, 5, 7};
    cout << lower_bound(v.begin(), v.end(), 3) - v.begin();
    return 0;
}

2130

Question 2
What must you do before calling unique to remove all duplicates?
Reverse the vectorSort itClear itNothing

Question 3

What does this print?

#include <iostream>
#include <vector>
#include <numeric>
using namespace std;
int main() {
    vector<int> v = {2, 4, 6};
    cout << accumulate(v.begin(), v.end(), 10);
    return 0;
}

12224810

Question 4
Which sorts a vector v in DESCENDING order?
sort(v.begin(), v.end())sort(v.begin(), v.end(), greater<int>())reverse(v.begin(), v.end()) alonesort(v.end(), v.begin())
Question 5
Why use ios::sync_with_stdio(false) in contests?
It's required by C++It makes cin/cout much faster for large input and outputIt enables printfIt sorts the input