Problem:


Score : 400 points

Problem Statement

There are N people standing in a queue from west to east.

Given is a string S of length N representing the directions of the people.
The i-th person from the west is facing west if the i-th character of S is L, and east if that character of S is R.

A person is happy if the person in front of him/her is facing the same direction.
If no person is standing in front of a person, however, he/she is not happy.

You can perform the following operation any number of times between 0 and K (inclusive):

Operation: Choose integers l and r such that 1 \leq l \leq r \leq N, and rotate by 180 degrees the part of the queue: the l-th, (l+1)-th, ..., r-th persons. That is, for each i = 0, 1, ..., r-l, the (l + i)-th person from the west will stand the (r - i)-th from the west after the operation, facing east if he/she is facing west now, and vice versa.

What is the maximum possible number of happy people you can have?

Constraints

N is an integer satisfying 1 \leq N \leq 10^5.

K is an integer satisfying 1 \leq K \leq 10^5.

|S| = N

Each character of S is L or R.

Input

Input is given from Standard Input in the following format:

N K
S

Output

Print the maximum possible number of happy people after at most K operations.

Sample Input 1

6 1
LRLRRL

Sample Output 1

3

If we choose (l, r) = (2, 5), we have LLLRLL, where the 2-nd, 3-rd, and 6-th persons from the west are happy.

Sample Input 2

13 3
LRRLRLRRLRLLR

Sample Output 2

9

Sample Input 3

10 1
LLLLLRRRRR

Sample Output 3

9

Sample Input 4

9 2
RRRLRLRLL

Sample Output 4

7



Sample input:
6 1
LRLRRL


Sample output:
3

Submission status: Wrong Answer

Solution code:
# -*- coding: utf-8 -*-
"""
Created on Sat Apr 20 20:47:47 2019

@author: Owner
"""

import numpy as np
import sys
import collections
import scipy.misc
import math
from operator import itemgetter
import itertools
import copy
import bisect
import heapq

#素因数を並べる
def prime_decomposition(n):
  i = 2
  table = []
  while i * i <= n:
    while n % i == 0:
      n /= i
      table.append(int(i))
    i += 1
  if n > 1:
    table.append(int(n))
  return table   
# 桁数を吐く
def digit(i):
    if i > 0:
        return digit(i//10) + [i%10]
    else:
        return []
    
def getNearestValueIndex(list, num):
    """
    概要: リストからある値に最も近い値のインデックスを取得する関数
    @param list: データ配列
    @param num: 対象値
    @return 対象値に最も近い値
    """

    # リスト要素と対象値の差分を計算し最小値のインデックスを取得
    idx = np.abs(np.asarray(list) - num).argmin()
    return idx

def find_index(l, x, default=False):
    if x in l:
        return l.index(x)
    else:
        return default

class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        """
        x が属するグループを探索
        """
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        """
        x と y のグループを結合
        """
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

    def is_same(self, x, y):
        """
        x と y が同じグループか否か
        """
        return self.find(x) == self.find(y)

    def get_size(self, x):
        """
        x が属するグループの要素数
        """
        x = self.find(x)
        return self.size[x]
    

"""
N, X = map(int, input().split())

x = list(map(int, input().split()))

P = [0]*N
Y = [0]*N
for n in range(N):
    P[n], Y[n] = map(int, input().split())

# 多次元配列の宣言（あとでintにすること。）（タプルにすること。）
dp = np.zeros((N+1, 4,4,4))
    
all(nstr.count(c) for c in '753')

# 複数配列を並び替え
ABT = zip(A, B, totAB)
result = 0
# itemgetterには何番目の配列をキーにしたいか渡します
sorted(ABT,key=itemgetter(2))
A, B, totAB = zip(*ABT)
A.sort(reverse=True)

# 2進数のbit判定
(x >> i) & 1

# dp最小化問題
dp = [np.inf]*N
for n in range(N):
    if n == 0:
        dp[n] = 0
    else:
        for k in range(1,K+1):
            if n-k >= 0:
                dp[n] = min(dp[n], dp[n-k] + abs(h[n]-h[n-k]))
            else:
                break
# 累積和
add = 1 # 問題によって決まる
res = 0
sums = [0]*(len(nums)+1)
for i in range(len(nums)):
    sums[i+1] = sums[i] + nums[i]
for i in range(0, len(nums), 2):
    left = i
    right = min(i+add, len(nums))
    tmp = sums[right] - sums[left]
    res = max(tmp, res)

#２分探索
li, ri = bisect.bisect_left(p_ac, l[i]-1), bisect.bisect_right(p_ac, r[i]-1)    

#ソート関数
org_list = [3, 1, 4, 5, 2]
new_list = sorted(org_list)
print(org_list)
print(new_list)
# [3, 1, 4, 5, 2]
# [1, 2, 3, 4, 5]

#Distance Transformation
    for h in range(0,H):
        for w in range(0,W):
            if h == 0 and w == 0:
                pass
            elif h == 0:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h-1][W-w]+1)
            elif w == 0:   
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1)
            else:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1, D[H-h-1][W-w]+1, D[H-h][W-w]+2)
            d_max = max(D[H-h-1][W-w-1], d_max)

"""


N, K = list(map(int, input().split()))
S = input()
    
def main():
    res = N
    past = S[0]
    cnt = K
    cnt2= 0
    if N == 1:
        return print(0)
    if N == 2:
        if (S[0] == "R" and S[1] == "L") or (S[0] == "L" and S[1] == "R"):
            if 0 < cnt:
                return print(1)
            else:
                return print(0)
        
        if (S[0] == "R" and S[1] == "R") or (S[0] == "L" and S[1] == "L"):
            return print(1)
    
    for n in range(1, N):
        now = S[n]
        #print(past, now, res)
        if past == "R" and now == "L":
            #print(n, ": BAD")
            res -= 2
            if 0 < cnt:
                #print("reverse")
                if not n == N-1:
                    res += 2
                else:
                    res += 1
                cnt -= 1
                cnt2 += 1
        past = now
    if  cnt2 == 1:
        return print(N-1)
    #print("Reach edge: ", res)
    if S[0] == "L":
        #print(0, ": edge BAD")
        res -= 1
        if 0 < cnt:
            #print("reverse")
            res += 1
            cnt -= 1        
    if S[-1] == "R":
        res -= 1
        #print(N-1, ": edge BAD")
        
    return print(res)
                
                
                
            
            
                

    
if __name__ == '__main__':
    main()

Submission status: Wrong Answer

Solution code:
# -*- coding: utf-8 -*-
"""
Created on Sat Apr 20 20:47:47 2019

@author: Owner
"""

import numpy as np
import sys
import collections
import scipy.misc
import math
from operator import itemgetter
import itertools
import copy
import bisect
import heapq

#素因数を並べる
def prime_decomposition(n):
  i = 2
  table = []
  while i * i <= n:
    while n % i == 0:
      n /= i
      table.append(int(i))
    i += 1
  if n > 1:
    table.append(int(n))
  return table   
# 桁数を吐く
def digit(i):
    if i > 0:
        return digit(i//10) + [i%10]
    else:
        return []
    
def getNearestValueIndex(list, num):
    """
    概要: リストからある値に最も近い値のインデックスを取得する関数
    @param list: データ配列
    @param num: 対象値
    @return 対象値に最も近い値
    """

    # リスト要素と対象値の差分を計算し最小値のインデックスを取得
    idx = np.abs(np.asarray(list) - num).argmin()
    return idx

def find_index(l, x, default=False):
    if x in l:
        return l.index(x)
    else:
        return default

class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        """
        x が属するグループを探索
        """
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        """
        x と y のグループを結合
        """
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

    def is_same(self, x, y):
        """
        x と y が同じグループか否か
        """
        return self.find(x) == self.find(y)

    def get_size(self, x):
        """
        x が属するグループの要素数
        """
        x = self.find(x)
        return self.size[x]
    

"""
N, X = map(int, input().split())

x = list(map(int, input().split()))

P = [0]*N
Y = [0]*N
for n in range(N):
    P[n], Y[n] = map(int, input().split())

# 多次元配列の宣言（あとでintにすること。）（タプルにすること。）
dp = np.zeros((N+1, 4,4,4))
    
all(nstr.count(c) for c in '753')

# 複数配列を並び替え
ABT = zip(A, B, totAB)
result = 0
# itemgetterには何番目の配列をキーにしたいか渡します
sorted(ABT,key=itemgetter(2))
A, B, totAB = zip(*ABT)
A.sort(reverse=True)

# 2進数のbit判定
(x >> i) & 1

# dp最小化問題
dp = [np.inf]*N
for n in range(N):
    if n == 0:
        dp[n] = 0
    else:
        for k in range(1,K+1):
            if n-k >= 0:
                dp[n] = min(dp[n], dp[n-k] + abs(h[n]-h[n-k]))
            else:
                break
# 累積和
add = 1 # 問題によって決まる
res = 0
sums = [0]*(len(nums)+1)
for i in range(len(nums)):
    sums[i+1] = sums[i] + nums[i]
for i in range(0, len(nums), 2):
    left = i
    right = min(i+add, len(nums))
    tmp = sums[right] - sums[left]
    res = max(tmp, res)

#２分探索
li, ri = bisect.bisect_left(p_ac, l[i]-1), bisect.bisect_right(p_ac, r[i]-1)    

#ソート関数
org_list = [3, 1, 4, 5, 2]
new_list = sorted(org_list)
print(org_list)
print(new_list)
# [3, 1, 4, 5, 2]
# [1, 2, 3, 4, 5]

#Distance Transformation
    for h in range(0,H):
        for w in range(0,W):
            if h == 0 and w == 0:
                pass
            elif h == 0:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h-1][W-w]+1)
            elif w == 0:   
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1)
            else:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1, D[H-h-1][W-w]+1, D[H-h][W-w]+2)
            d_max = max(D[H-h-1][W-w-1], d_max)

"""


N, K = list(map(int, input().split()))
S = input()
    
def main():
    res = N
    past = S[0]
    cnt = K
    cnt2= 0
    if N == 1:
        return print(0)
    if N == 2:
        if (S[0] == "R" and S[1] == "L") or (S[0] == "L" and S[1] == "R"):
            if 0 < cnt:
                return print(1)
            else:
                return print(0)
        
        if (S[0] == "R" and S[1] == "R") or (S[0] == "L" and S[1] == "L"):
            return print(1)
    
    for n in range(1, N):
        now = S[n]
        #print(past, now, res)
        if past == "R" and now == "L":
            #print(n, ": BAD")
            res -= 2
            if 0 < cnt:
                #print("reverse")
                if not n == N-1:
                    res += 2
                else:
                    res += 1
                cnt -= 1
                cnt2 += 1
        past = now
    if  cnt2 == 1:
        return print(res-1)
    #print("Reach edge: ", res)
    if S[0] == "L":
        #print(0, ": edge BAD")
        res -= 1
        if 0 < cnt:
            #print("reverse")
            res += 1
            cnt -= 1        
    if S[-1] == "R":
        res -= 1
        #print(N-1, ": edge BAD")
        
    return print(res)
                
                
                
            
            
                

    
if __name__ == '__main__':
    main()

Submission status: Wrong Answer

Solution code:
N,K = map(int,input().split())
P = list(input())
count = 0
for i in range(N-1):
    if P[i] == P[i+1]:
        count += 1
time = 0
for i in range(1,N):
    if P[i] != P[i-1]:
        time += 1
if time == 1:
    print(count + 1)
else:
    print(count + 2*min(K,time))

Submission status: Wrong Answer

Solution code:
N,K = map(int,input().split())
P = list(input())
count = 0
for i in range(N-1):
    if P[i] == P[i+1]:
        count += 1
time = 0
for i in range(1,N):
    if P[i] != P[i-1]:
        time += 1
if time == 1:
    print(count + 1)
else:
    print(count + 2*min(K,time))

Submission status: Wrong Answer

Solution code:
N,K = map(int,input().split())
s = str(input())

ans = N - 1 - s.count('RL') - s.count('LR')
print(min( N-1 , ans - 2 * K ))

Submission status: Wrong Answer

Solution code:
import sys
n, k = map(int, input().split(' '))
s = str(input())

i = 0
counter = 1
assyuku = [1]
while i+counter < n:
    if s[i] == s[i+counter]:
        assyuku[-1] += 1
        counter += 1
    else:
        assyuku.append(1)
        i += counter
        counter = 1
assyuku = [x-1 for x in assyuku]
if len(assyuku) > k*2:
    print(sum(assyuku)+2*k)
else:
    print(sum(assyuku)+2*k-1)

Submission status: Wrong Answer

Solution code:
import sys
n, k = map(int, input().split(' '))
s = str(input())

i = 0
counter = 1
assyuku = [1]
while i+counter < n:
    if s[i] == s[i+counter]:
        assyuku[-1] += 1
        counter += 1
    else:
        assyuku.append(1)
        i += counter
        counter = 1
assyuku = [x-1 for x in assyuku]
print(sum(assyuku)+2*k)

Submission status: Wrong Answer

Solution code:
# -*- coding: utf-8 -*-
"""
Created on Sat Apr 20 20:47:47 2019

@author: Owner
"""

import numpy as np
import sys
import collections
import scipy.misc
import math
from operator import itemgetter
import itertools
import copy
import bisect
import heapq

#素因数を並べる
def prime_decomposition(n):
  i = 2
  table = []
  while i * i <= n:
    while n % i == 0:
      n /= i
      table.append(int(i))
    i += 1
  if n > 1:
    table.append(int(n))
  return table   
# 桁数を吐く
def digit(i):
    if i > 0:
        return digit(i//10) + [i%10]
    else:
        return []
    
def getNearestValueIndex(list, num):
    """
    概要: リストからある値に最も近い値のインデックスを取得する関数
    @param list: データ配列
    @param num: 対象値
    @return 対象値に最も近い値
    """

    # リスト要素と対象値の差分を計算し最小値のインデックスを取得
    idx = np.abs(np.asarray(list) - num).argmin()
    return idx

def find_index(l, x, default=False):
    if x in l:
        return l.index(x)
    else:
        return default

class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        """
        x が属するグループを探索
        """
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        """
        x と y のグループを結合
        """
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

    def is_same(self, x, y):
        """
        x と y が同じグループか否か
        """
        return self.find(x) == self.find(y)

    def get_size(self, x):
        """
        x が属するグループの要素数
        """
        x = self.find(x)
        return self.size[x]
    

"""
N, X = map(int, input().split())

x = list(map(int, input().split()))

P = [0]*N
Y = [0]*N
for n in range(N):
    P[n], Y[n] = map(int, input().split())

# 多次元配列の宣言（あとでintにすること。）（タプルにすること。）
dp = np.zeros((N+1, 4,4,4))
    
all(nstr.count(c) for c in '753')

# 複数配列を並び替え
ABT = zip(A, B, totAB)
result = 0
# itemgetterには何番目の配列をキーにしたいか渡します
sorted(ABT,key=itemgetter(2))
A, B, totAB = zip(*ABT)
A.sort(reverse=True)

# 2進数のbit判定
(x >> i) & 1

# dp最小化問題
dp = [np.inf]*N
for n in range(N):
    if n == 0:
        dp[n] = 0
    else:
        for k in range(1,K+1):
            if n-k >= 0:
                dp[n] = min(dp[n], dp[n-k] + abs(h[n]-h[n-k]))
            else:
                break
# 累積和
add = 1 # 問題によって決まる
res = 0
sums = [0]*(len(nums)+1)
for i in range(len(nums)):
    sums[i+1] = sums[i] + nums[i]
for i in range(0, len(nums), 2):
    left = i
    right = min(i+add, len(nums))
    tmp = sums[right] - sums[left]
    res = max(tmp, res)

#２分探索
li, ri = bisect.bisect_left(p_ac, l[i]-1), bisect.bisect_right(p_ac, r[i]-1)    

#ソート関数
org_list = [3, 1, 4, 5, 2]
new_list = sorted(org_list)
print(org_list)
print(new_list)
# [3, 1, 4, 5, 2]
# [1, 2, 3, 4, 5]

#Distance Transformation
    for h in range(0,H):
        for w in range(0,W):
            if h == 0 and w == 0:
                pass
            elif h == 0:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h-1][W-w]+1)
            elif w == 0:   
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1)
            else:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1, D[H-h-1][W-w]+1, D[H-h][W-w]+2)
            d_max = max(D[H-h-1][W-w-1], d_max)

"""


N, K = list(map(int, input().split()))
S = input()
    
def main():
    res = N
    past = S[0]
    cnt = K
    if N == 1:
        return print(0)
    if N == 2:
        if (S[0] == "R" and S[1] == "L") or (S[0] == "L" and S[1] == "R"):
            if 0 < cnt:
                return print(1)
            else:
                return print(0)
        
        if (S[0] == "R" and S[1] == "R") or (S[0] == "L" and S[1] == "L"):
            return print(1)
    
    for n in range(1, N):
        now = S[n]
        #print(past, now, res)
        if past == "R" and now == "L":
            #print(n, ": BAD")
            res -= 2
            if 0 < cnt:
                #print("reverse")
                if not n == N-1:
                    res += 2
                else:
                    res += 1
                cnt -= 1
        past = now
    #print("Reach edge: ", res)
    if S[0] == "L":
        #print(0, ": edge BAD")
        res -= 1
        if 0 < cnt:
            #print("reverse")
            res += 1
            cnt -= 1        
    if S[-1] == "R":
        res -= 1
        #print(N-1, ": edge BAD")
        
    return print(res)
                
                
                
            
            
                

    
if __name__ == '__main__':
    main()

Submission status: Wrong Answer

Solution code:
# -*- coding: utf-8 -*-
"""
Created on Sat Apr 20 20:47:47 2019

@author: Owner
"""

import numpy as np
import sys
import collections
import scipy.misc
import math
from operator import itemgetter
import itertools
import copy
import bisect
import heapq

#素因数を並べる
def prime_decomposition(n):
  i = 2
  table = []
  while i * i <= n:
    while n % i == 0:
      n /= i
      table.append(int(i))
    i += 1
  if n > 1:
    table.append(int(n))
  return table   
# 桁数を吐く
def digit(i):
    if i > 0:
        return digit(i//10) + [i%10]
    else:
        return []
    
def getNearestValueIndex(list, num):
    """
    概要: リストからある値に最も近い値のインデックスを取得する関数
    @param list: データ配列
    @param num: 対象値
    @return 対象値に最も近い値
    """

    # リスト要素と対象値の差分を計算し最小値のインデックスを取得
    idx = np.abs(np.asarray(list) - num).argmin()
    return idx

def find_index(l, x, default=False):
    if x in l:
        return l.index(x)
    else:
        return default

class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        """
        x が属するグループを探索
        """
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        """
        x と y のグループを結合
        """
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

    def is_same(self, x, y):
        """
        x と y が同じグループか否か
        """
        return self.find(x) == self.find(y)

    def get_size(self, x):
        """
        x が属するグループの要素数
        """
        x = self.find(x)
        return self.size[x]
    

"""
N, X = map(int, input().split())

x = list(map(int, input().split()))

P = [0]*N
Y = [0]*N
for n in range(N):
    P[n], Y[n] = map(int, input().split())

# 多次元配列の宣言（あとでintにすること。）（タプルにすること。）
dp = np.zeros((N+1, 4,4,4))
    
all(nstr.count(c) for c in '753')

# 複数配列を並び替え
ABT = zip(A, B, totAB)
result = 0
# itemgetterには何番目の配列をキーにしたいか渡します
sorted(ABT,key=itemgetter(2))
A, B, totAB = zip(*ABT)
A.sort(reverse=True)

# 2進数のbit判定
(x >> i) & 1

# dp最小化問題
dp = [np.inf]*N
for n in range(N):
    if n == 0:
        dp[n] = 0
    else:
        for k in range(1,K+1):
            if n-k >= 0:
                dp[n] = min(dp[n], dp[n-k] + abs(h[n]-h[n-k]))
            else:
                break
# 累積和
add = 1 # 問題によって決まる
res = 0
sums = [0]*(len(nums)+1)
for i in range(len(nums)):
    sums[i+1] = sums[i] + nums[i]
for i in range(0, len(nums), 2):
    left = i
    right = min(i+add, len(nums))
    tmp = sums[right] - sums[left]
    res = max(tmp, res)

#２分探索
li, ri = bisect.bisect_left(p_ac, l[i]-1), bisect.bisect_right(p_ac, r[i]-1)    

#ソート関数
org_list = [3, 1, 4, 5, 2]
new_list = sorted(org_list)
print(org_list)
print(new_list)
# [3, 1, 4, 5, 2]
# [1, 2, 3, 4, 5]

#Distance Transformation
    for h in range(0,H):
        for w in range(0,W):
            if h == 0 and w == 0:
                pass
            elif h == 0:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h-1][W-w]+1)
            elif w == 0:   
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1)
            else:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1, D[H-h-1][W-w]+1, D[H-h][W-w]+2)
            d_max = max(D[H-h-1][W-w-1], d_max)

"""


N, K = list(map(int, input().split()))
S = input()
    
def main():
    res = N
    past = S[0]
    cnt = K
    
    if N == 2:
        if (S[0] == "R" and S[1] == "L") or (S[0] == "L" and S[1] == "R"):
            if 0 < cnt:
                return print(1)
            else:
                return print(0)
        
        if (S[0] == "R" and S[1] == "R") or (S[0] == "L" and S[1] == "L"):
            return print(1)
    
    for n in range(1, N):
        now = S[n]
        #print(past, now, res)
        if past == "R" and now == "L":
            #print(n, ": BAD")
            res -= 2
            if 0 < cnt:
                #print("reverse")
                if not n == N-1:
                    res += 2
                else:
                    res += 1
                cnt -= 1
        past = now
    #print("Reach edge: ", res)
    if S[0] == "L":
        #print(0, ": edge BAD")
        res -= 1
        if 0 < cnt:
            #print("reverse")
            res += 1
            cnt -= 1        
    if S[-1] == "R":
        res -= 1
        #print(N-1, ": edge BAD")
        
    return print(res)
                
                
                
            
            
                

    
if __name__ == '__main__':
    main()

Submission status: Wrong Answer

Solution code:
# -*- coding: utf-8 -*-
"""
Created on Sat Apr 20 20:47:47 2019

@author: Owner
"""

import numpy as np
import sys
import collections
import scipy.misc
import math
from operator import itemgetter
import itertools
import copy
import bisect
import heapq

#素因数を並べる
def prime_decomposition(n):
  i = 2
  table = []
  while i * i <= n:
    while n % i == 0:
      n /= i
      table.append(int(i))
    i += 1
  if n > 1:
    table.append(int(n))
  return table   
# 桁数を吐く
def digit(i):
    if i > 0:
        return digit(i//10) + [i%10]
    else:
        return []
    
def getNearestValueIndex(list, num):
    """
    概要: リストからある値に最も近い値のインデックスを取得する関数
    @param list: データ配列
    @param num: 対象値
    @return 対象値に最も近い値
    """

    # リスト要素と対象値の差分を計算し最小値のインデックスを取得
    idx = np.abs(np.asarray(list) - num).argmin()
    return idx

def find_index(l, x, default=False):
    if x in l:
        return l.index(x)
    else:
        return default

class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        """
        x が属するグループを探索
        """
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        """
        x と y のグループを結合
        """
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

    def is_same(self, x, y):
        """
        x と y が同じグループか否か
        """
        return self.find(x) == self.find(y)

    def get_size(self, x):
        """
        x が属するグループの要素数
        """
        x = self.find(x)
        return self.size[x]
    

"""
N, X = map(int, input().split())

x = list(map(int, input().split()))

P = [0]*N
Y = [0]*N
for n in range(N):
    P[n], Y[n] = map(int, input().split())

# 多次元配列の宣言（あとでintにすること。）（タプルにすること。）
dp = np.zeros((N+1, 4,4,4))
    
all(nstr.count(c) for c in '753')

# 複数配列を並び替え
ABT = zip(A, B, totAB)
result = 0
# itemgetterには何番目の配列をキーにしたいか渡します
sorted(ABT,key=itemgetter(2))
A, B, totAB = zip(*ABT)
A.sort(reverse=True)

# 2進数のbit判定
(x >> i) & 1

# dp最小化問題
dp = [np.inf]*N
for n in range(N):
    if n == 0:
        dp[n] = 0
    else:
        for k in range(1,K+1):
            if n-k >= 0:
                dp[n] = min(dp[n], dp[n-k] + abs(h[n]-h[n-k]))
            else:
                break
# 累積和
add = 1 # 問題によって決まる
res = 0
sums = [0]*(len(nums)+1)
for i in range(len(nums)):
    sums[i+1] = sums[i] + nums[i]
for i in range(0, len(nums), 2):
    left = i
    right = min(i+add, len(nums))
    tmp = sums[right] - sums[left]
    res = max(tmp, res)

#２分探索
li, ri = bisect.bisect_left(p_ac, l[i]-1), bisect.bisect_right(p_ac, r[i]-1)    

#ソート関数
org_list = [3, 1, 4, 5, 2]
new_list = sorted(org_list)
print(org_list)
print(new_list)
# [3, 1, 4, 5, 2]
# [1, 2, 3, 4, 5]

#Distance Transformation
    for h in range(0,H):
        for w in range(0,W):
            if h == 0 and w == 0:
                pass
            elif h == 0:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h-1][W-w]+1)
            elif w == 0:   
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1)
            else:
                D[H-h-1][W-w-1]= min(D[H-h-1][W-w-1], D[H-h][W-w-1]+1, D[H-h-1][W-w]+1, D[H-h][W-w]+2)
            d_max = max(D[H-h-1][W-w-1], d_max)

"""


N, K = list(map(int, input().split()))
S = input()
    
def main():
    res = N
    past = S[0]
    cnt = K
    
    if N == 2:
        if (S[0] == "R" and S[1] == "L") or (S[0] == "L" and S[1] == "R"):
            return print(0)
        if (S[0] == "R" and S[1] == "R") or (S[0] == "L" and S[1] == "L"):
            return print(1)
    
    for n in range(1, N):
        now = S[n]
        #print(past, now, res)
        if past == "R" and now == "L":
            #print(n, ": BAD")
            res -= 2
            if 0 < cnt:
                #print("reverse")
                if not n == N-1:
                    res += 2
                else:
                    res += 1
                cnt -= 1
        past = now
    #print("Reach edge: ", res)
    if S[0] == "L":
        #print(0, ": edge BAD")
        res -= 1
        if 0 < cnt:
            #print("reverse")
            res += 1
            cnt -= 1        
    if S[-1] == "R":
        res -= 1
        #print(N-1, ": edge BAD")
        
    return print(res)
                
                
                
            
            
                

    
if __name__ == '__main__':
    main()