955. Delete Columns to Make Sorted II
Description
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[0] <= strs[1] <= strs[2] <= ... <= 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[0] <= strs[1] <= strs[2]). 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[0][0] <= strs[0][1] <= ...)
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.
Solutions
Solution 1
Java Code

