Ternary Search Algorithm With Example

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int N,i,low,mid1,mid2,high,key,position=-1;
    cout << "Enter the length of array" << endl;
    cin >> N; // Taking length of array as input
    int input_array[N];
    cout << "Enter array elements in increasing order" << endl;
    for(i=0;i<N;i++) // loop to take array elements as input
    {
        cin >> input_array[i];
    }
    cout << "Enter the element to be searched" << endl;
    cin >> key; // taking key as input
    low=0; // initialising low to 0 because initially sub-array is the input_array
    high=N-1; // initialising high to N-1 because initially sub-array is the input_array
    while(low<=high) // the index of first element of sub-array is always less than or equal to the index of last element of sub-array
    {
        mid1 = low + (high - low)/3; // finding the value of mid1
        mid2 = high - (high - low)/3; // finding the value of mid2
        if(key==input_array[mid1]) // checking if key is equal to the array element at mid1
        {
            position = mid1; // if yes, storing the value of mid1 and stopping the search
            break;
        }
        else if(key==input_array[mid2]) // checking if key is equal to the array element at mid2
        {
            position = mid2; // if yes, storing the value of mid2 and stopping the search
            break;
        }
        else if(key < input_array[mid1]) // checking if key is less than array element at mid1
        {
            high = mid1 - 1; // if yes, sub-array ends at mid1-1
        }
        else if(key > input_array[mid2]) // checking if key is greater than array element at mid2
        {
            low = mid2 + 1; // if yes, sub-array starts from mid2+1
        }
        else
        {
            /* if the value of key is greater than array element at mid1 and less than array element at mid2, 
            sub-array starts at mid1+1 and ends at mid2-1 */
            low = mid1 + 1;
            high = mid2 - 1;
        }
    }
    if(position >= 0) // checking if position is greater or equal to zero
    {
        cout << "key found at index " << position << endl; // if yes, key is found at index position of input_array
    }
    else // if not, key is not found in input_array
    {
        cout << "key is not found in the array" << endl;
    }
    return 0;
}