CF1194B Yet Another Crosses Problem

题目描述

你将会得到若干个 $n$ 行 $m$ 列的矩阵。每一格都被涂成了黑色或白色 若矩阵中的某行,某列都为黑色,则这一行与一列构成了一个十字架 如下所示,这些矩阵都包含了至少一个十字架 ![qaq](https://cdn.luogu.org/upload/vjudge_pic/CF1194B/88ab70f483371a989bc0a7f4c7494f932bf59239.png) 而下列矩阵则不包含十字架 ![233](https://cdn.luogu.org/upload/vjudge_pic/CF1194B/a3af39e3883913d8cb154cdd61325299208144f4.png) 你的任务是,共有 $q$ 次询问。对于每一次询问,给出一个矩阵,求出至少还要将多少个白色格子涂成黑色,才能使这个矩阵包含至少一个十字架

输入格式

第一行包含了一个正整数 $q (1 \leq q \leq 5 \times 10^4)$,意义如上 在每一个询问中,第一行包含了两个正整数 $n, m(1 \leq n, m \leq 5 \times 10^4, n \times m \leq 4 \times 10^5)$,意义如上 接下来会给出 $n$ 行字符,每行 $m$ 个。若第 $i$ 行 $j$ 个字符为 '.',则代表矩阵的第 $i, j$ 格为白色,'*' 代表黑色 保证 $\displaystyle \sum n \leq 5 \times 10^4$ 且 $\displaystyle \sum n \times m \leq 4 \times 10^5$

输出格式

输出 $q$ 行,每行包含一个正整数,要求如上

说明/提示

The example contains all the pictures from above in the same order. The first 5 pictures already contain a cross, thus you don't have to paint anything. You can paint $ (1, 3) $ , $ (3, 1) $ , $ (5, 3) $ and $ (3, 5) $ on the $ 6 $ -th picture to get a cross in $ (3, 3) $ . That'll take you $ 4 $ minutes. You can paint $ (1, 2) $ on the $ 7 $ -th picture to get a cross in $ (4, 2) $ . You can paint $ (2, 2) $ on the $ 8 $ -th picture to get a cross in $ (2, 2) $ . You can, for example, paint $ (1, 3) $ , $ (3, 1) $ and $ (3, 3) $ to get a cross in $ (3, 3) $ but that will take you $ 3 $ minutes instead of $ 1 $ . There are 9 possible crosses you can get in minimum time on the $ 9 $ -th picture. One of them is in $ (1, 1) $ : paint $ (1, 2) $ and $ (2, 1) $ .