Today I have done leetcode's December LeetCoding Challenge with cpp.

December LeetCoding Challenge 20

Description

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 follows:

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.

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  int minDeletionSize(vector<string>& strs) {
    int len = strs.front().length();
    int count = strs.size();
    int answer = 0;
    for(int i = 0; i < len; ++i) {
      string cur(count, 0);
      for(int j = 0; j < count; ++j) {
        cur[j] = strs[j][i];
      }
      answer += !is_sorted(cur.begin(), cur.end());
    }
    return answer;
  }
};

// Accepted
// 85/85 cases passed (44 ms)
// Your runtime beats 87.58 % of cpp submissions
// Your memory usage beats 10.77 % of cpp submissions (14.9 MB)