leetcode 944 Delete Columns to Make Sorted

class Solution {
public:
    int minDeletionSize(vector<string>& A) {
        //删除每一列非升序子序列；
        int cnt=0;
        for(int j=0;j<A[0].size();j++){
            for(int i=1;i<A.size();i++){
                if(A[i][j]<A[i-1][j]){
                    cnt++;break;
                }
            }
        }
        return cnt;
    }
};