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: Accepted

Solution code:
def main(sample_file = ''):

    """ convenient functions
    # for i, a in enumerate(iterable)
    # q, mod = divmod(a, b)
    # divmod(x, y) returns the tuple (x//y, x%y)
    # Higher-order function: reduce(operator.mul, xyz_count, 1)
    # manage median(s) using two heapq https://atcoder.jp/contests/abc127/tasks/abc127_f
    """

    """convenient decorator
    # @functools.lru_cache():
    # to facilitate use of recursive function
        # ex:
        # from functools import lru_cache
        # import sys
        # sys.setrecursionlimit(10**9)
        # @lru_cache(maxsize=None)
        # def fib(n):
        #     if n < 2:
        #         return n
        #     return fib(n-1) + fib(n-2)
        # print(fib(1000))
    """
    
    # import numpy as np
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product # https://docs.python.org/ja/3/library/itertools.html
    # accumulate() returns iterator! to get list: list(accumulate())
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  # prime factor
        b, e = 2, 0  # base, exponent
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        # TODO: How should I do when n - r is negative?
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict # https://docs.python.org/ja/3/library/collections.html#collections.deque
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest # https://docs.python.org/ja/3/library/heapq.html
    from copy import deepcopy, copy # https://docs.python.org/ja/3/library/copy.html
    import operator
    from operator import itemgetter #sort 
    # ex1: List.sort(key=itemgetter(1))
    # ex2: sorted(tuples, key=itemgetter(1,2))
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd # Deprecated since version 3.5: Use math.gcd() instead.
    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)
    
    # first create factorial_list
    # fac_list = mod_factorial_list(n)
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    modpow = lambda a, n, p = MOD: pow(a, n, p) # Recursive function in python is slow!
    def modinv(a, p = MOD):
        # evaluate reciprocal using Fermat's little theorem:
        # a**(p-1) is identical to 1 (mod p) when a and p is coprime
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        # fac_list = modfactorial_list(100)
        # print(modcomb(100, 5, modfactorial_list(100)))
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something
        >>  else:
        >>      do something
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    # Graph: https://en.wikipedia.org/wiki/Directed_graph
    # Bellman-Ford: O(|V||E|). Use this if there exists an edge with negative length in the graph
    # After N steps, the shortest path has converded if there doesn't exist an cycle of edges with negative
    # Watch out: d[N] == d[2*N] doesn't necessarily mean the graph doesn't have negative cycle
    # ref: https://www.youtube.com/watch?v=1Z6ofKN03_Y

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    """ initialize variables and set inputs
    # initialize variables
        # to initialize list, use [0] * n
        # to initialize two dimentional array, use [[0] * N for _ in range(N)]
    # set inputs
        # put inputs between specific values (almost as quickly)
        # ex) S = [-INF] + [int(r()) for _ in range(A)] + [INF]
        # open(0).read() is sometimes useful:
        # ex) n, m, *x = map(int, open(0).read().split())
        #     min(x[::2]) - max(x[1::2])
        # ex2) *x, = map(int, open(0).read().split())
        #     don't forget to add comma after *x if only one variable is used
    # preprocessing
        # transpose = [x for x in zip(*data)]
        # ex) [[1, 2, 3], [4, 5, 6], [7, 8, 9]] => [(1, 4, 7), (2, 5, 8), (3, 6, 9)]
        # flat = [flatten for inner in data for flatten in inner]
        # ex) [[1, 2, 3], [4, 5, 6], [7, 8, 9]] => [1, 2, 3, 4, 5, 6, 7, 8, 9]
    # calculate and output
        # output pattern
        # ex1) print(*l) => when l = [2, 5, 6], printed 2 5 6
    """

    # functions to read input
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    R = lambda: list(map(int, r().split()))
    Rmap = lambda: map(int, r().split())
    Rfloat = lambda: list(map(float, r().split()))
    Rtuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    # single int: int(r())
    # single string: r()
    # single float: float(r())
    # line int: R()
    # line string: r().split()
    # line (str, int, int): [j if i == 0 else int(j) for i, j in enumerate(r().split())]
    # lines int: [R() for _ in range(n)]
    """

    # for test
    if sample_file:
        sys.stdin = open(sample_file)
        
    # ----------------------------------
    # main

    N, K = R()
    S = r()
    lr = 0
    rl = 0
    pr = S[0]
    ans = 0
    for s in S[1:]:
        if pr == 'L' and s == 'R':
            lr += 1
        elif pr == 'R' and s == 'L':
            rl += 1
        elif pr == s:
            ans += 1
        pr = s
    mn = min(lr, rl)
    ans += min(K, mn) * 2
    if K - mn > 0:
        ans += min(K-mn, max(lr, rl)-mn)
    print(ans)

    # to finish code, use return instead of exit()
    # end of main
    # ----------------------------------

    """memo: how to use defaultdict of list
    # initialize
    Dic = defaultdict(list)
    # append / extend
    Dic[x].append(y)
    # three methods for loop: keys(), values(), items()
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    # to make binary digits text
    >>> a = 5
    >>> bin_str_a = format(a, '#06b')
    >>> print(bin_str_a)
    0b0101 # first 2 strings (='0b') indicates it is binary
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
n,k = map(int,input().split())
s = input()
h = 0
if s[0] == 'R':
    if s[1] == 'R':
        h = h+1

if s[n-1] == 'L':
    if s[n-2] == 'L':
        h = h+1
        
for i in range(1,n-1):
    if s[i] == 'R':
        if s[i+1] == 'R':
            h = h+1
    else:
        if s[i-1] == 'L':
            h = h+1

if (h + 2*k) >= n:
    print(n-1)
else:
    print(h + 2*k)

Submission status: Accepted

Solution code:
#!/usr/bin/env python3
import sys
from itertools import groupby


def solve(N: int, K: int, S: str):
    L = [len(list(g)) for k, g in groupby(S)]
    score = N - len(L)
    plus = min(2*K, len(L)-1)
    score += plus
    print(score)
    return


# Generated by 1.1.5 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  # type: int
    K = int(next(tokens))  # type: int
    S = next(tokens)  # type: str
    solve(N, K, S)

if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
n,k=map(int,input().split())
statas=input()
subs=[]
count=1
buf=statas[0]
for string in statas[1:]:
    if buf==string:
        count+=1
    else:
        subs.append(count)
        count=1
        buf=string
if (len(subs)+1)//2 <= k:
    print(n-1)
else:
    print(n-1-len(subs)+2*k)

Submission status: Accepted

Solution code:
n,k = map(int,input().split())	
s=list(input())
a=0
b=0
c=0
for i in range(n-1):
    if(s[i]=="L" and s[i+1]=="R"):
        a+=1
    elif(s[i]=="R" and s[i+1]=="L"):
        b+=1
    else:
        c+=1
ans=c+min(a,b,k)*2
if( min(a,b,k)<k ):
    q=min(a,b,k)
    a-=q
    b-=q
    if((a==0 and b==1) or (a==1 and b==0)):
        ans+=1
    
print(ans)

Submission status: Accepted

Solution code:
#!/usr/bin/env python3
import sys


def solve(N: int, K: int, S: str):
    count = 0
    for i in range(N-1):
        if S[i] == S[i+1]:
            count += 1
    print(min(count + K * 2, N-1))
    return


# Generated by 1.1.5 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  # type: int
    K = int(next(tokens))  # type: int
    S = next(tokens)  # type: str
    solve(N, K, S)

if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
def resolve():
    n,k=map(int,input().split())
    S=input()
    lr=0
    rl=0
    score=0
    for i in range(n-1):
        score+=(S[i]==S[i+1])
        lr+=(S[i]=="L" and S[i+1]=="R")
        rl+=(S[i]=="R" and S[i+1]=="L")
    print(score+min(k,lr)+min(k,rl))
resolve()

Submission status: Accepted

Solution code:
import sys
def input():
    return sys.stdin.readline()[:-1]
inf=float("inf")
n,k=map(int,input().split())
s=input()
cnt=[]
tmp=[1,s[0]]
for i in range(1,n):
    if s[i]==tmp[1]:
        tmp[0]+=1
    else:
        cnt.append(tmp[0])
        tmp=[1,s[i]]
cnt.append(tmp[0])
# print(cnt)
ans=sum(cnt[:1+2*k])
left=0
right=0
for i in range(len(cnt)-1-2*k):
    right+=cnt[1+2*k+i]-1
# print(right)
tmp=left+ans+right
for i in range(len(cnt)-1-2*k):
    tmp1=left+ans+right
    left+=cnt[i]-1
    ans+=cnt[i+1+2*k]-cnt[i]
    right-=cnt[i+1+2*k]+1
    if tmp1<left+ans+right:
        tmp=left+ans+right
print(tmp-1)

Submission status: Accepted

Solution code:
#!/usr/bin/env python3
import sys


def solve(N: int, K: int, S: str):
    count = 0
    for i in range(N-1):
        if S[i] == S[i+1]:
            count += 1
    result = min(count + K * 2, N-1)
    print(result)
    return


# Generated by 1.1.5 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  # type: int
    K = int(next(tokens))  # type: int
    S = next(tokens)  # type: str
    solve(N, K, S)

if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
import sys

sys.setrecursionlimit(10**7)
INF = 10 ** 18
MOD = 10 ** 9 + 7
def LI(): return list(map(int, sys.stdin.readline().split()))
def II(): return int(sys.stdin.readline())
def LS(): return list(map(list, sys.stdin.readline().split()))
def S(): return list(sys.stdin.readline())[:-1]

def main():
    n, k = LI()
    s = S()
    conb = []
    for i in range(n-1):
        conb.append(s[i] == s[i+1])
    print(min(sum(conb) + k * 2, n-1))




if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
N,K = map(int, input().split())
S = input()
Ans = 0
max = N - 1

for i in range(N-1):
  if S[i] == S[i+1]:
    Ans = Ans + 1

Ans = Ans + 2 * K
if Ans >= max:
  Ans = max

print(Ans)

Submission status: Accepted

Solution code:
N, K = [ int(n) for n in input().split() ]
S = input()

happy = 0
LR = 0
RL = 0
for i in range(N-1):
    s = S[i:i+2]
    if s == "LR":
        LR += 1
    elif s == "RL":
        RL += 1
    else:
        happy += 1

m = min(LR,RL)
M = max(LR,RL)
if M <= K:
    print(N-1)
elif m >= K:
    print(happy + 2*K)
else:
    print(N-2)

Submission status: Accepted

Solution code:
n, k = map(int, input().split())
s = list(input())
sn = []
cur = None
for c in s:
    if cur is not None:
        if c == cur:
            sn[-1] += 1
        else:
            sn.append(1)
    else:
        sn = [1]
    cur = c

while len(sn) >= 3:
    if k == 0:
        break
    a, b, c = sn.pop(), sn.pop(), sn.pop()
    sn.append(a+b+c)
    k -= 1
if k > 0:
    if len(sn) == 3:
        sn = [sn[0] + sn[1] + sn[2]]
    elif len(sn) == 2:
        sn = [sn[0] + sn[1]]

score = sum([s - 1 for s in sn])
print(score)

Submission status: Accepted

Solution code:
n, k = map(int, input().split())
prev = ''
cnt = 0
for c in input():
    if c != prev: cnt += 1
    prev = c
cnt = max(1, cnt - 2 * k)
print(n - cnt)

Submission status: Accepted

Solution code:
import sys
input = sys.stdin.readline

def main():
    N,K = map(int,input().split())
    S = input()[:-1]

    score = 0
    for i in range(N-1):
        if S[i] == S[i+1]:
            score += 1

    print(min(score+2*K,N-1))

if __name__ == "__main__":
    main()

Submission status: Accepted

Solution code:
# coding: utf-8
# Your code here!
n,k=map(int,input().split())
S=list(input())
tmp=0
cnt=-1

for i in range(n):
    if tmp!=S[i]:
        cnt+=1
    tmp=S[i]

if k*2>=cnt:
    print(n-1)
else:
    print(n-1-cnt+k*2)

Submission status: Accepted

Solution code:
N,K=[int(x) for x in input().split()]
S=input()
bg=S[0]
t=0
A=[]
for i in range(N):
    if S[i]==bg:
        t+=1
    else:
        A.append(t)
        bg=S[i]
        t=1
A.append(t)
ans=N - max( (len(A)-2*K) , 1)
print(ans)

Submission status: Accepted

Solution code:
n, k = map(int, input().split())
S = input()

boundaries = list()
for i in range(n - 1):
    c1, c2 = S[i], S[i + 1]
    if c1 != c2:
        boundaries.append(i)

ans = n - 1 - len(boundaries)
if len(boundaries) % 2 == 0:
    ans += (2 * min(k, len(boundaries) // 2))

else:
    if len(boundaries) // 2 + 1 <= k:
        ans += len(boundaries)
    elif len(boundaries) // 2 <= k:
        ans += (len(boundaries) - 1)
    else:
        ans += (2 * k)

print(ans)

Submission status: Accepted

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

Submission status: Accepted

Solution code:
n,k = [int(i) for i in input().split()]
s = input()
diff = 0

before = s[0]
for i in range(1,n):
    if before!=s[i]:
        diff += 1
    before = s[i]

diff -= 2*k
diff = max(0,diff) + 1
print(n-diff)

Submission status: Accepted

Solution code:
N, K = map(int, input().split())
S = input()
ans = 0
for i in range(N-1):
    if S[i] == S[i+1]:
        ans+=1
print(min(ans+K*2, N-1))

Submission status: Accepted

Solution code:
n,k=map(int,input().split())
S=list(input())
cnt=0
x=0

for i in range(1,n):
    if S[i]==S[i-1]:
        cnt+=1
    else:
        x+=cnt
        cnt=0
x+=cnt
print(min(x+2*k,n-1))

Submission status: Accepted

Solution code:
n, k =map(int,input().split())
s = input()
islands=1
for i in range(1, len(s)):
	if s[i] != s[i-1]:
		islands+=1
print(n - max(1,islands-2*k))

Submission status: Accepted

Solution code:
N, K = map(int, input().split())
S = input()
happy = 0
LR = 0
RL = 0
for i in range(N-1):
    if S[i] == S[i+1]:
        happy += 1
    elif S[i] == 'L':
        LR += 1
    else:
        RL += 1
turn = min(K, LR, RL)
happy += turn * 2
K -= turn
LR -= turn
RL -= turn
LRturn = min(K, LR)
happy += LRturn
K -= LRturn
LR -= LRturn
RLturn = min(K, RL)
happy += RLturn
K -= RLturn
RL -= RLturn
print(happy)

Submission status: Accepted

Solution code:
n, k = map(int, input().split())
s = input()

mae = s[0]
cnt = 0
happy = 0

if mae == "R":
    if n>=2:
        if s[1]=="R":
            happy += 1

for i in range(1,n):
    now = s[i]

    if now=="L":
        if mae=="L":
            happy += 1
    if now=="R":
        if i<n-1:
            if s[i+1]=="R":
                happy+=1


    if now != mae:
        cnt += 1

    mae = now

n_set = cnt//2
n_amari = cnt%2

if k <= n_set:
    happy += k*2
else:
    happy += n_set*2+n_amari

print(happy)

Submission status: Accepted

Solution code:
import sys
sys.setrecursionlimit(10**7)
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x) - 1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def II(): return int(sys.stdin.readline())
def SI(): return sys.stdin.readline().strip()
INF = 10 ** 18
MOD = 10 ** 9 + 7

debug = True
debug = False

def dprint(*objects):
    if debug == True:
        print(*objects)


def solve():
    N, K = LI()
    S = SI()


    point = 0
    for i in range(N):
        if i != 0:
            if S[i] == S[i-1]:
                point += 1

    rest_len = N-point
    # rest_len_aft_k = rest_len - 2*K
    # dprint(rest_len, rest_len_aft_k)
    # if rest_len_aft_k <= 1:
    #     print(N)
    # else:
    print(min(point + 2*K, N-1))

solve()

Submission status: Accepted

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

c = 0
for i in range(N-1):
    if S[i] != S[i+1]:
        c += 1

if K*2 <= c:
    ans = N-1-c+K*2
else:
    ans = N-1
print(ans)

Submission status: Accepted

Solution code:
n, k = map(int, input().split())
s = input()
if n == 1:
    print(0)
else:
    happy = 0
    if s[0] == "R" and s[1] == "R":
        happy += 1
    if s[n - 1] == "L" and s[n - 2] == "L":
        happy += 1
    for i in range(1, n - 1):
        if s[i] == "L":
            if s[i - 1] == "L":
                happy += 1
        else:
            if s[i + 1] == "R":
                happy += 1
    lr = 0
    rl = 0
    for i in range(n - 1):
        if s[i] == "L" and s[i + 1] == "R":
            lr += 1
        elif s[i] == "R" and s[i + 1] == "L":
            rl += 1
    for i in range(k):
        if min(lr, rl) >= 1:
            happy += 2
            lr -= 1
            rl -= 1
        elif max(lr, rl) >= 1:
            happy += 1
            lr = max(lr - 1, 0)
            rl = max(rl - 1, 0)
    print(happy)

Submission status: Accepted

Solution code:
n, k = map(int, input().split())
s = input()

ans = 0
count = 1
for i in range(n-1):
    if s[i] == s[i+1]:
        ans += 1
    else:
        count += 1

for i in range(k):
    if count >= 3:
        count -= 2
        ans += 2
    elif count == 2:
        count -= 1
        ans += 1
    elif count == 1:
        break

print(ans)

Submission status: Accepted

Solution code:
n, k  = map(int, input().split())
s = list(input())

left = 0
right = n-1
count = 0
border = 0
tag = s[0]
if s[right] != tag:
    while s[right] != tag:
        right-=1
    border +=1
while True:
    while s[left] == tag and left < right:
        left+=1
    while s[right] == tag and left <= right:
        right -= 1
    if left == right:
        border += 2
        break
    if right < left:
        break
    border += 2
    if tag == 'L':
        tag = 'R'
    else:
        tag = 'L'

border = max(0, border - k * 2)
print(n - border -1)

Submission status: Accepted

Solution code:
(N,M) = (int(i) for i in input().split(" "))
S = input()
T = [S[0]]
for i in range(1,len(S)):
	if T[-1][-1] != S[i]:
		T.append(S[i])
	else:
		T[-1]+=S[i]
mp = [len(t) for t in T]
ans = len(S) - len(mp) + M*2
print(min(ans,len(S)-1))

Submission status: Accepted

Solution code:
n,k=map(int,input().split())
s=input()
s="x"+s+"x"
lr,rl=0,0
ans=0
for i in range(1,n+1):
  if s[i]=="L":
    if s[i-1]=="L":
      ans+=1
    if s[i+1]=="R":
      lr+=1
  else:
    if s[i+1]=="R":
      ans+=1
    elif s[i+1]=="L":
      rl+=1
if k<=min(lr,rl):
  ans+=2*k
else:
  ans+=2*min(lr,rl)
  k-=min(lr,rl)
  if k>=abs(lr-rl):
    ans+=abs(lr-rl)
  else:
    ans+=k
print(ans)

Submission status: Accepted

Solution code:
N, K = map(int, input().split())
S = 'R' + input() + 'L'
UH = [0] * (N + 1)
d = 'R'
for i, s in enumerate(S):
  if s == 'R':
    if S[i + 1] == 'L':
      UH[i] += 1
  else:
    if S[i - 1] == 'R':
      UH[i - 1] += 1
UH[0] = min(UH[0], 1)
UH[N] = min(UH[N], 1)
UH.sort(reverse=True)
for i in range(min(K, N + 1)):
  UH[i] = 0
if sum(UH) == 0:
  UH[0] = 1
print(N - sum(UH))

Submission status: Accepted

Solution code:

N,K = map(int,input().split())
S = list(input())

ans = 0
if S[0] == 'R':
    flagr = True
else:
    flagr = False

for i in range(1,N):
    if flagr:
        if S[i] == 'R':
            ans += 1
        else:
            flagr = False
    else:
        if S[i] == 'L':
            ans += 1
        else:
            flagr = True
            
ans = min(ans+2*K,N-1)
print(ans)

Submission status: Accepted

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

dup = 0
for i in range(1,N):
    if S[i] == S[i-1]:
        dup += 1
print(min(N-1, dup + K*2))