0955.cpp

static int x = []() {std::ios::sync_with_stdio(false); cin.tie(0); return 0; }();
class Solution 
{
public:
    int minDeletionSize(vector<string>& A) 
    {
        int res = 0, n = A.size(), m = A[0].length(), i;
        vector<bool> sorted(n-1, false);
        for (int j = 0; j < m; ++j) 
        {
            for (i = 0; i < n - 1; ++i) 
            {
                if (!sorted[i] && A[i][j] > A[i + 1][j]) 
                {
                    res++; break;
                }
            }
            if (i < n - 1) continue;
            for (i = 0; i < n - 1; ++i)
            {
                if (A[i][j] < A[i + 1][j]) sorted[i] = true;
            }            
        }
        return res;
    }
};