minimum-steps-get-given-desired-array.cpp

/* C++ program to count minimum number of operations
   to get the given target array */
#include <bits/stdc++.h>
using namespace std;

// Returns count of minimum operations to covert a
// zero array to target array with increment and
// doubling operations.
// This function computes count by doing reverse
// steps, i.e., convert target to zero array.
int countMinOperations(unsigned int target[], int n)
{
    // Initialize result (Count of minimum moves)
    int result = 0;

    // Keep looping while all elements of target
    // don't become 0.
    while (1)
    {
        // To store count of zeroes in current
        // target array
        int zero_count = 0;

        int i;  // To find first odd element
        for (i=0; i<n; i++)
        {
            // If odd number found
            if (target[i] & 1)
                break;

            // If 0, then increment zero_count
            else if (target[i] == 0)
                zero_count++;
        }

        // All numbers are 0
        if (zero_count == n)
          return result;

        // All numbers are even
        if (i == n)
        {
            // Divide the whole array by 2
            // and increment result
            for (int j=0; j<n; j++)
               target[j] = target[j]/2;
            result++;
        }

        // Make all odd numbers even by subtracting
        // one and increment result.
        for (int j=i; j<n; j++)
        {
           if (target[j] & 1)
           {
              target[j]--;
              result++;
           }
        }
    }
}

/* Driver program to test above functions*/
int main()
{
    unsigned int arr[] = {16, 16, 16};
    int n = sizeof(arr)/sizeof(arr[0]);
    cout << "Minimum number of steps required to "
           "get the given target array is "
         << countMinOperations(arr, n);
    return 0;
}