Problem:
Score : 400 points

Problem Statement

At an arcade, Takahashi is playing a game called RPS Battle, which is played as follows:

The player plays N rounds of Rock Paper Scissors against the machine. (See Notes for the description of Rock Paper Scissors. A draw also counts as a round.)

Each time the player wins a round, depending on which hand he/she uses, he/she earns the following score (no points for a draw or a loss):

R points for winning with Rock;

S points for winning with Scissors;

P points for winning with Paper.

However, in the i-th round, the player cannot use the hand he/she used in the (i-K)-th round. (In the first K rounds, the player can use any hand.)

Before the start of the game, the machine decides the hand it will play in each round. With supernatural power, Takahashi managed to read all of those hands.

The information Takahashi obtained is given as a string T. If the i-th character of T (1 \leq i \leq N) is r, the machine will play Rock in the i-th round. Similarly, p and s stand for Paper and Scissors, respectively.

What is the maximum total score earned in the game by adequately choosing the hand to play in each round?

Notes

In this problem, Rock Paper Scissors can be thought of as a two-player game, in which each player simultaneously forms Rock, Paper, or Scissors with a hand.

If a player chooses Rock and the other chooses Scissors, the player choosing Rock wins;

if a player chooses Scissors and the other chooses Paper, the player choosing Scissors wins;

if a player chooses Paper and the other chooses Rock, the player choosing Paper wins;

if both players play the same hand, it is a draw.

Constraints

2 \leq N \leq 10^5

1 \leq K \leq N-1

1 \leq R,S,P \leq 10^4

N,K,R,S, and P are all integers.

|T| = N

T consists of r, p, and s.

Input

Input is given from Standard Input in the following format:

N K
R S P
T

Output

Print the maximum total score earned in the game.

Sample Input 1

5 2
8 7 6
rsrpr

Sample Output 1

27

The machine will play {Rock, Scissors, Rock, Paper, Rock}.

We can, for example, play {Paper, Rock, Rock, Scissors, Paper} against it to earn 27 points.
We cannot earn more points, so the answer is 27.

Sample Input 2

7 1
100 10 1
ssssppr

Sample Output 2

211

Sample Input 3

30 5
325 234 123
rspsspspsrpspsppprpsprpssprpsr

Sample Output 3

4996

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AtCoder2 {
	class Program {
		static void Main(string[] args) {

			var inputArray = retreiveLongArray();
			var inputCount = 2;

			// 不正な入力は処理しない
			if (inputArray.Length != inputCount) {
				Console.WriteLine("invalid input");
				return;
			}
			var N = inputArray[0];
			var K = inputArray[1];

			var pointArray = retreiveLongArray();
			var R = pointArray[2];//コンピューターがrの時得られる点数
			var S = pointArray[0];//上記と同じ考え
			var P = pointArray[1];
			var janken = retreiveStringArray()[0];

			var rList = new HashSet<long>();
			var sList = new HashSet<long>();
			var pList = new HashSet<long>();

			//r,s,pそれぞれが何番目に出てくるかを記録する
			for (int i = 0; i < N; i++) {
				var ch = janken[i];

				if (ch == 'r') {
					rList.Add(i);
				}
				if (ch == 's') {
					sList.Add(i);
				}
				if (ch == 'p') {
					pList.Add(i);
				}
			}
			//K回目　同じ手出せないときの制約を考えないときのポイント
			var unrestrictPoint = R * rList.Count() + S * sList.Count() + P * pList.Count();

			var rLoss = calLossPoint(K, R,rList);
			var sLoss = calLossPoint(K, S, sList);
			var pLoss = calLossPoint(K, P, pList);



			//答えの出力
			var ans = unrestrictPoint- rLoss- sLoss- pLoss;
			Console.WriteLine(ans);

		}

		/// <summary>
		/// 同じ手を出せないことによって生じる損失点数
		/// </summary>
		/// <param name="K"></param>
		/// <param name="point"></param>
		/// <param name="jankenList"></param>
		/// <returns></returns>
		private static long calLossPoint(long K, long point, HashSet<long> jankenList) {

			var changeList = new HashSet<long>();//K番先に同じ手がある場合、書き換える。書き換えた番号を覚えておくリスト
			var count = 0;
			foreach (var r in jankenList) {

				if (changeList.Contains(r)) {
					continue;
				}

				if (jankenList.Contains(r + K)) {
					count++;
					changeList.Add(r + K);
				}
			}
			return point * count;
		}

		/// <summary>
		/// スペースで区切られた文字列配列の入力を受け取る
		/// </summary>
		/// <returns></returns>
		private static string[] retreiveStringArray() {
			var inputArray = Console.ReadLine().Split(' ');
			return inputArray;
		}

		/// <summary>
		/// スペースで区切られた整数配列の入力を受け取る
		/// </summary>
		/// <returns></returns>
		private static long[] retreiveLongArray() {
			var inputArray = Console.ReadLine().Split(' ');
			var longArray = inputArray.Select(s => long.Parse(s));
			return longArray.ToArray();
		}
	}
}