hard question

Question

How do you delete all the duplicates in the areay? Assume there are 10 integers in the array(numbers could repeat), what algorithm should i use to make sure all the numbers appear only once.

Answer 1

Sounds like what you really want to use is a set. A set doesn't allow duplicates. If you need to convert an array to a set here is some example code.

#include <iostream>
#include <set>

using namespace std;

int main() {
int arr[] = {1,2,3,4,5,5,6,4,6,7,8};
set<int> s(begin(arr), end(arr));

for(set<int>::iterator it = s.begin(); it != s.end(); ++it) {
cout << *it << endl;
}
return 0;
}

If you just want to use a set outright:

#include <iostream>
#include <set>

using namespace std;

int main() {
set<int> s{1,2,3,4,5,6,7,8,9,2,3,4,5}; //initialize with curly braces

for(set<int>::iterator it = s.begin(); it != s.end(); ++it) {
cout << *it << endl;
}
return 0;
}

OR:

#include <iostream>
#include <set>

using namespace std;

int main() {
set<int> s;
s.insert(1);
s.insert(2);
s.insert(3);
s.insert(4);
s.insert(2); // won't be added to set
s.insert(4); // won't be added to set
s.insert(3); // won't be added to set

for(set<int>::iterator it = s.begin(); it != s.end(); ++it) {
cout << *it << endl;
}
return 0;
}