Fastest way to search for an element in unsorted array

Question

I just bumped on to this question today and was trying for a solution that is better than O(N) but could not come up with one.

Searched through SO but couldn\'t find

Answer 1

You can search an element with O(1) using this approach.

Just create a MAP . When you insert a value just then for that key assign value to '1', and to search it again just check if that array is present or not .

Below is the code:-

#include

using namespace std;

int main(){
    int n;
    cin>>n;
    map map;
    for(int i=0;i>k;
        map[k]=1;
    }
    int num;
    cin>>num;

    if(map[num]){
        cout<<"FOUND"<

Output :FOUND