Buggy python submission (verdict: Time Limit Exceeded):
import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

# 前からと後ろからでcandに入れて両方に入るところ
N, K, C = lr()
S = sr()
cand1 = set()
cand2 = set()

def F(S):
    cand = set()
    count = 0
    cur = 0
    while cur < len(S):
        if S[cur] == 'o':
            count += 1
            cand.add(cur)
            cur += C+1            
        else:
            cur += 1
        if count >= K:
            break
    return cand

cand1 = F(S)
cand2 = F(S[::-1])
cand2 = set(N-1-x for x in cand2)
s = cand1 & cand2
s = sorted(list(s))
s = [x+1 for x in s]

def check(S):
    count = 0
    cur = 0
    while cur < len(S):
        if S[cur] == 'o':
            count += 1
            cur += C+1            
        else:
            cur += 1
        if count >= K:
            return True
    return False

for x in s:
    T = list(S)
    T[x-1] = 'x'
    if not check(T):
        print(x)


Fixed submission:
import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

# 前からと後ろからでgreedyにcandに入れて両方の一致したところ
N, K, C = lr()
S = sr()

def choose(S):
    cand = []
    count = 0
    cur = 0
    while cur < len(S):
        if S[cur] == 'o':
            count += 1
            cand.append(cur)
            cur += C+1            
        else:
            cur += 1
        if count >= K:
            break
    return cand

cand1 = choose(S)
cand2 = choose(S[::-1])[::-1]
cand2 = [N-1-x for x in cand2]

for x, y in zip(cand1, cand2):
    if x == y:
        print(x+1)

Buggy python submission (verdict: Time Limit Exceeded):
import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

# 前からと後ろからでcandに入れて両方に入るところ
N, K, C = lr()
S = sr()
cand1 = set()
cand2 = set()

def F(S):
    cand = set()
    count = 0
    cur = 0
    while cur < len(S):
        if S[cur] == 'o':
            count += 1
            cand.add(cur)
            cur += C+1            
        else:
            cur += 1
        if count >= K:
            break
    return cand

cand1 = F(S)
cand2 = F(S[::-1])
cand2 = set(N-1-x for x in cand2)
s = cand1 & cand2
s = sorted(list(s))
s = [x+1 for x in s]

def check(S):
    count = 0
    cur = 0
    while cur < len(S):
        if S[cur] == 'o':
            count += 1
            cur += C+1            
        else:
            cur += 1
        if count >= K:
            return True
    return False

for x in s:
    T = list(S)
    T[x-1] = 'x'
    if not check(T):
        print(x)


Fixed submission:
import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

# 前からと後ろからでgreedyにcandに入れて両方の一致したところ
N, K, C = lr()
S = sr()

def choose(S):
    cand = []
    count = 0
    cur = 0
    while cur < len(S):
        if S[cur] == 'o':
            count += 1
            cand.append(cur)
            cur += C+1            
        else:
            cur += 1
        if count >= K:
            break
    return cand

cand1 = choose(S)
cand2 = choose(S[::-1])[::-1]
cand2 = [N-1-x for x in cand2]

for x, y in zip(cand1, cand2):
    if x == y:
        print(x+1)