CF1647B.Madoka and the Elegant Gift

Madoka's father just reached $1$ million subscribers on Mathub! So the website decided to send him a personalized award — The Mathhub's Bit Button!

The Bit Button is a rectangular table with $n$ rows and $m$ columns with $0$ or $1$ in each cell. After exploring the table Madoka found out that:

• A subrectangle $A$ is contained in a subrectangle $B$ if there's no cell contained in $A$ but not contained in $B$.
• Two subrectangles intersect if there is a cell contained in both of them.
• A subrectangle is called black if there's no cell with value $0$ inside it.
• A subrectangle is called nice if it's black and it's not contained in another black subrectangle.
• The table is called elegant if there are no two nice intersecting subrectangles.

For example, in the first illustration the red subrectangle is nice, but in the second one it's not, because it's contained in the purple subrectangle.

Help Madoka to determine whether the table is elegant.

魔理沙的父亲刚刚在 Mathub 网站上达到了 100 万订阅者！因此，该网站决定向他颁发一枚专属奖章——Mathhub 的“比特按钮”（Bit Button）！

“比特按钮”是一个具有 $n$ 行 $m$ 列的矩形表格，每个格子中填有 $0$ 或 $1$。魔理沙在研究该表格时发现：

• 子矩形 $A$ 包含于子矩形 $B$，当且仅当不存在属于 $A$ 却不属于 $B$ 的格子；
• 两个子矩形相交，当且仅当存在一个格子同时属于这两个子矩形；
• 一个子矩形被称为黑色的，当且仅当其内部不包含值为 $0$ 的格子；
• 一个子矩形被称为优美的，当且仅当它是黑色的，且不被任何其他黑色子矩形所包含；
• 整个表格被称为优雅的，当且仅当其中不存在两个相交的优美子矩形。

例如，在第一张示意图中，红色子矩形是优美的；但在第二张图中它却不是优美的，因为它被紫色子矩形所包含。

请帮助魔理沙判断该表格是否为优雅的。

Each test contains multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 200$) — the number of test cases. Description of the test cases follows.

The first line of each test case contains two positive integers $n, m$ ($1 \le n, m \le 100$).

The next $n$ lines contain strings of length $m$ consisting of zeros and ones — the description of the table.

It is guaranteed that the sum of the values of $n$ and the sum of the values of $m$ for all test cases do not exceed $777$.

每个测试包含多个测试用例。第一行包含一个整数 $t$（$1 \le t \le 200$），表示测试用例的数量。随后是各测试用例的描述。

每个测试用例的第一行包含两个正整数 $n, m$（$1 \le n, m \le 100$）。

接下来的 $n$ 行，每行包含一个长度为 $m$ 的字符串，仅由字符 0 和 1 组成——表示表格的描述。

保证所有测试用例中 $n$ 的总和与 $m$ 的总和均不超过 $777$。

For each test case print "YES" if its table is elegant or print "NO" otherwise.

You may print each letter in any case (for example, "YES", "Yes", "yes", "yEs" will all be recognized as positive answer).

对于每个测试用例，如果其表格是优美的，则输出 “YES”，否则输出 “NO”。

你可以以任意大小写形式输出每个字母（例如，“YES”、“Yes”、“yes”、“yEs” 均会被识别为肯定回答）。

In the second test case the table is not elegant, because the red and the purple subrectangles are nice and intersect.

In the fourth test case the table is not elegant, because the red and the purple subrectangles are nice and intersect.

在第二个测试用例中，该表格不优雅，因为红色和紫色子矩形都是优美的且相交。

在第四个测试用例中，该表格不优雅，因为红色和紫色子矩形都是优美的且相交。