2038. Long Distance Racing

单点时限: 2.0 sec

内存限制: 256 MB

Bessie is training for her next race by running on a path that includes hills so that she will be prepared for any terrain. She has planned a straight path and wants to run as far as she can – but she must be back to the farm within M seconds (1 <= M <=

10,000,000).

The entire path she has chosen is T units (1 <= T <= 100,000) in length and consists of equal-length portions that are uphill, flat, or downhill. The input data describes path segment i with a single character S_i that is u, f, or d, indicating respectively uphill,

flat, or downhill.

Bessie takes U seconds (1 <= U <= 100) to run one unit of uphill path, F (1 <= F <= 100) seconds for a unit of flat path, and D (1 <= D <= 100) seconds for a unit of downhill path. Note that, when returning home, uphill paths become downhill paths and downhill

paths become uphill paths.

Find the farthest distance Bessie can get from the farm and still make it back in time.

输入格式

  • Line 1: Five space-separated integers: M, T, U, F, and D

  • Lines 2..T+1: Line i+1 describes path segment i with a single letter: S_i

输出格式

  • Line 1: A single integer that is the farthest distance (number of units) that Bessie can get from the farm and make it back in time.

样例

Input
13 5 3 2 1
u
f
u
d
f
INPUT DETAILS:
Bessie has 13 seconds to get home (short workout!), and the total path she has planned is 5 units long. She can run an uphill unit in 3 seconds, a flat unit in 2 seconds, and a downhill unit in 1 seconds. The path looks like this:
_/\_
/
Output
3
OUTPUT DETAILS:
She can run three units and back in 3 + 2 + 3 + 1 + 2 + 1 = 12 seconds, just a second less than her limit. If she tried to go farther she would not make it.

59 人解决,60 人已尝试。

67 份提交通过,共有 100 份提交。

2.3 EMB 奖励。

创建: 16 年,4 月前.

修改: 6 年,9 月前.

最后提交: 11 月,1 周前.

来源: USACO

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