Gas Pipeline

题意翻译

你需要在城市里修建管道和支柱,管道和支柱的单位长度的价格分别为$a,b$ 给你一个长度为$n$的$01$序列,其中$1$表示这里需要通车,$0$表示这里不需要通车,高度为$2$的地方才可以通车(保证序列的头尾不需要通车) 如图,红色表示管道,黑色表示支柱,我们可以在一段单位区间建立一条S形线条,每个S形可以表示为该段由三部分组成:$0.5$个单位的水平管道+$1$个单位的垂直管道+$0.5$个单位的水平管道 每一段的单位区间左右都有支柱支撑,支柱的高度等于管道端点的高度 你需要保证所有通车的地方高度为$2$的同时,建管道和支柱的费用总和最小

题目描述

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. ![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF1207C/f1dfe38b83de03ccc78e9e23fedbdc3223f970d0.png)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.

输入输出格式

输入格式


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 $ .

输出格式


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

输入输出样例

输入样例 #1

4
8 2 5
00110010
8 1 1
00110010
9 100000000 100000000
010101010
2 5 1
00

输出样例 #1

94
25
2900000000
13

说明

The optimal pipeline for the first query is shown at the picture above. The optimal pipeline for the second query is pictured below: ![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF1207C/2782d7e4c7012251045217f9f050b1e333f47c33.png)The optimal (and the only possible) pipeline for the third query is shown below: ![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF1207C/7e72ed8fa647ff66b04ca0425394c874c1b110fe.png)The optimal pipeline for the fourth query is shown below: ![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF1207C/248de9c02a0298296e2131b26213178e9c6ad6ba.png)