## Algorithm

Problem Name: 955. Delete Columns to Make Sorted II

You are given an array of `n` strings `strs`, all of the same length.

We may choose any deletion indices, and we delete all the characters in those indices for each string.

For example, if we have `strs = ["abcdef","uvwxyz"]` and deletion indices `{0, 2, 3}`, then the final array after deletions is `["bef", "vyz"]`.

Suppose we chose a set of deletion indices `answer` such that after deletions, the final array has its elements in lexicographic order (i.e., `strs <= strs <= strs <= ... <= strs[n - 1]`). Return the minimum possible value of `answer.length`.

Example 1:

```Input: strs = ["ca","bb","ac"]
Output: 1
Explanation:
After deleting the first column, strs = ["a", "b", "c"].
Now strs is in lexicographic order (ie. strs <= strs <= strs).
We require at least 1 deletion since initially strs was not in lexicographic order, so the answer is 1.
```

Example 2:

```Input: strs = ["xc","yb","za"]
Output: 0
Explanation:
strs is already in lexicographic order, so we do not need to delete anything.
Note that the rows of strs are not necessarily in lexicographic order:
i.e., it is NOT necessarily true that (strs <= strs <= ...)
```

Example 3:

```Input: strs = ["zyx","wvu","tsr"]
Output: 3
Explanation: We have to delete every column.
```

Constraints:

• `n == strs.length`
• `1 <= n <= 100`
• `1 <= strs[i].length <= 100`
• `strs[i]` consists of lowercase English letters.

## Code Examples

### #1 Code Example with Javascript Programming

```Code - Javascript Programming```

``````
const minDeletionSize = function (A) {
const set = new Set()
const m = A.length
let res = 0
if(m === 0) return 0
const n = A.length
for(j = 0; j < n; j++) {
if(set.size === m - 1) return res
for(i = 0; i < m - 1; i++) {
if(!set.has(i) && A[i][j] > A[i + 1][j]) {
res++
break
}
}
if(i < m - 1) continue
for(i = 0; i < m - 1; i++) {
if(A[i][j] < A[i + 1][j]) set.add(i)
}
}

return res
}
``````
Copy The Code &

Input

cmd
strs = ["ca","bb","ac"]

Output

cmd
1

### #2 Code Example with Python Programming

```Code - Python Programming```

``````
class Solution:
def minDeletionSize(self, A):
res = 0
cur = [""] * len(A)
for col in zip(*A):
cur2 = list(zip(cur, col))
if cur2 == sorted(cur2):
cur = cur2
else:
res += 1
return res
``````
Copy The Code &

Input

cmd
strs = ["ca","bb","ac"]

Output

cmd
1