0960.cpp

static int x = []() {std::ios::sync_with_stdio(false); cin.tie(0); return 0; }();
class Solution 
{
public:
    int minDeletionSize(vector<string>& A) 
    {
        vector<int> mem(A[0].size(), 1);
        for (int i = 0; i < A[0].size(); ++i) 
        {
            for (int j = 0; j < i; ++j)
            {
                for (int k = 0; k <= A.size(); ++k) 
                {
                    if (k == A.size()) mem[i] = max(mem[i], mem[j] + 1);
                    else if (A[k][j] > A[k][i]) break;
                }               
            }
        }
        return A[0].size() - *max_element(begin(mem), end(mem));
    }
};