Codeforces Round 911 (Div. 2) |
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Finished |
Filip has a row of cells, some of which are blocked, and some are empty. He wants all empty cells to have water in them. He has two actions at his disposal:
If at some moment cell $$$i$$$ ($$$2 \le i \le n-1$$$) is empty and both cells $$$i-1$$$ and $$$i+1$$$ contains water, then it becomes filled with water.
Find the minimum number of times he needs to perform action $$$1$$$ in order to fill all empty cells with water.
Note that you don't need to minimize the use of action $$$2$$$. Note that blocked cells neither contain water nor can Filip place water in them.
Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 100$$$). The description of the test cases follows.
The first line of each test case contains a single integer $$$n$$$ ($$$1 \le n \le 100$$$) — the number of cells.
The next line contains a string $$$s$$$ of length $$$n$$$. The $$$i$$$-th character of $$$s$$$ is '.' if the cell $$$i$$$ is empty and '#' if cell $$$i$$$ is blocked.
For each test case, output a single number — the minimal amount of actions $$$1$$$ needed to fill all empty cells with water.
53...7##....#7..#.#..4####10#...#..#.#
2 2 5 0 2
Test Case 1
In the first test case, Filip can put water in cells $$$1$$$ and $$$3$$$. As cell $$$2$$$ is between $$$2$$$ cells with water, it gets filled with water too.
Test Case 2
In the second case, he can put water sources in cells $$$3$$$ and $$$5$$$. That results in cell $$$4$$$ getting filled with water. Then he will remove water from cell $$$5$$$ and place it into cell $$$6$$$. As cell $$$5$$$'s neighbors, cell $$$4$$$ and cell $$$6$$$, have water in them, cell $$$5$$$ also gets filled with water. You can see the illustration of this case below.
Test Case 3
In the third case, he can put water in all the empty cells. That requires $$$5$$$ actions of type $$$1$$$.
Test Case 4
In the fourth case, there are no empty cells. Therefore, he does not have to put any water in them.
Test Case 5
In the fifth test case, there exists a sequence of actions that requires only $$$2$$$ type $$$1$$$ actions.
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