C. Gas Pipeline
time limit per test
2 seconds
memory limit per test
256 megabytes
standard input
standard output

You are responsible for installing a gas pipeline along a road. Let's consider the road (for simplicity) as a segment $$$[0, n]$$$ on $$$OX$$$ axis. The road can have several crossroads, but for simplicity, we'll denote each crossroad as an interval $$$(x, x + 1)$$$ with integer $$$x$$$. So we can represent the road as a binary string consisting of $$$n$$$ characters, where character 0 means that current interval doesn't contain a crossroad, and 1 means that there is a crossroad.

Usually, we can install the pipeline along the road on height of $$$1$$$ unit with supporting pillars in each integer point (so, if we are responsible for $$$[0, n]$$$ road, we must install $$$n + 1$$$ pillars). But on crossroads we should lift the pipeline up to the height $$$2$$$, so the pipeline won't obstruct the way for cars.

We can do so inserting several zig-zag-like lines. Each zig-zag can be represented as a segment $$$[x, x + 1]$$$ with integer $$$x$$$ consisting of three parts: $$$0.5$$$ units of horizontal pipe + $$$1$$$ unit of vertical pipe + $$$0.5$$$ of horizontal. Note that if pipeline is currently on height $$$2$$$, the pillars that support it should also have length equal to $$$2$$$ units.

Each unit of gas pipeline costs us $$$a$$$ bourles, and each unit of pillar — $$$b$$$ bourles. So, it's not always optimal to make the whole pipeline on the height $$$2$$$. Find the shape of the pipeline with minimum possible cost and calculate that cost.

Note that you must start and finish the pipeline on height $$$1$$$ and, also, it's guaranteed that the first and last characters of the input string are equal to 0.


The fist line contains one integer $$$T$$$ ($$$1 \le T \le 100$$$) — the number of queries. Next $$$2 \cdot T$$$ lines contain independent queries — one query per two lines.

The first line contains three integers $$$n$$$, $$$a$$$, $$$b$$$ ($$$2 \le n \le 2 \cdot 10^5$$$, $$$1 \le a \le 10^8$$$, $$$1 \le b \le 10^8$$$) — the length of the road, the cost of one unit of the pipeline and the cost of one unit of the pillar, respectively.

The second line contains binary string $$$s$$$ ($$$|s| = n$$$, $$$s_i \in \{0, 1\}$$$, $$$s_1 = s_n = 0$$$) — the description of the road.

It's guaranteed that the total length of all strings $$$s$$$ doesn't exceed $$$2 \cdot 10^5$$$.


Print $$$T$$$ integers — one per query. For each query print the minimum possible cost of the constructed pipeline.

8 2 5
8 1 1
9 100000000 100000000
2 5 1

The optimal pipeline for the first query is shown at the picture above.

The optimal pipeline for the second query is pictured below:

The optimal (and the only possible) pipeline for the third query is shown below:

The optimal pipeline for the fourth query is shown below: