Harsh Rajpal

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# 944. Delete Columns to make sorted

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

The strings can be arranged such that there is one on each line, making a grid. For example, strs = ["abc", "bce", "cae"] can be arranged as:

abc
bce
cae
You want to delete the columns that are not sorted lexicographically. In the above example (0-indexed), columns 0 ('a', 'b', 'c') and 2 ('c', 'e', 'e') are sorted while column 1 ('b', 'c', 'a') is not, so you would delete column 1.

Return the number of columns that you will delete.

Example 1:

Input: strs = ["cba","daf","ghi"]
Output: 1
Explanation: The grid looks as follows:
cba
daf
ghi
Columns 0 and 2 are sorted, but column 1 is not, so you only need to delete 1 column.
Example 2:

Input: strs = ["a","b"]
Output: 0
Explanation: The grid looks as follows:
a
b
Column 0 is the only column and is sorted, so you will not delete any columns.
Example 3:

Input: strs = ["zyx","wvu","tsr"]
Output: 3
Explanation: The grid looks as follows:
zyx
wvu
tsr
All 3 columns are not sorted, so you will delete all 3.

Constraints:

n == strs.length
1 <= n <= 100
1 <= strs[i].length <= 1000
strs[i] consists of lowercase English letters.

``````class Solution {
public int minDeletionSize(String[] strs) {
int count = 0; // number of columns to delete
for (int i = 0; i < strs[0].length(); i++)// loop through each column
{
for (int j = 0; j < strs.length - 1; j++)//// loop through each row
{
if (strs[j].charAt(i) > strs[j + 1].charAt(i)) // compare the current column with the next column
{
count++;// if the current column is not sorted, increment the count
break;
}
}
}
return count;// return the number of columns to delete
}
}
``````