https://leetcode.cn/problems/delete-columns-to-make-sorted/
class Solution {
public int minDeletionSize(String[] strs) {
int m=strs.length;
int n=strs[0].length();
int count=0;
for(int i=0;i<n;i++){
char before='a';
for(int j=0;j<m;j++){
if(strs[j].charAt(i)>=before){
before=strs[j].charAt(i);
}
else{
count++;
break;
}
}
}
return count;
}
}