Delete Columns to Make Sorted

We are given an array A of N lowercase letter strings, all of the same length.
Now, we may choose any set of deletion indices, and for each string, we delete all the characters in those indices.
For example, if we have an array A = ["abcdef","uvwxyz"] and deletion indices {0, 2, 3}, then the final array after deletions is ["bef", "vyz"], and the remaining columns of A are ["b","v"], ["e","y"], and ["f","z"].  (Formally, the c-th column is [A[0][c], A[1][c], ..., A[A.length-1][c]]).
Suppose we chose a set of deletion indices D such that after deletions, each remaining column in A is in non-decreasing sorted order.
Return the minimum possible value of D.length.

Example 1:

Input: A = ["cba","daf","ghi"]
Output: 1

Approach

Java

public class DelColMakeSorted {
    public static void main(String[] args) {
        String str[] = { "cba", "daf", "ghi" };
        System.out.println(minDeletionSize(str));
    }

    public static int minDeletionSize(String[] A) {
        int D = 0;
        int len = A[0].length();
        // iterate till end of list
        for (int j = 0; j < len; j++) {
            int flag = 0;
            // iterate all list
            for (int i = 0; i < A.length - 1; i++) {
                if (A[i].charAt(j) > A[i + 1].charAt(j)) {
                    flag = 1;
                    break;
                }
            }
            if (flag == 1)
                D++;
        }
        return D;
    }
}

C++

#include <bits/stdc++.h>
using namespace std;


int minDeletionSize(vector<string>& A)
{
       vector<int> D;
      int len=A[0].size();
      for(int j=0;j<len;j++)
      {
         int flag=0;
       for(int i=0;i<A.size()-1;i++)
        {
           if(A[i][j]>A[i+1][j])
           {
               flag=1;
               break;
           }
        }
          if(flag==1)
                D.push_back(j);
      }
        return D.size();
}
int main()
{
    vector<string> str ={"cba","daf","ghi"};
    cout<<minDeletionSize(str);
    return 0;
}