Buggy python submission (verdict: Time Limit Exceeded):
def main():
    n, k, c = map(int, input().split())
    s = input()

    if c == 0:
        if s.count('o') == k:
            ret = [i for i, c in enumerate(s) if c == 'o']
        else:
            ret = []

    else:

        go = set()
        back = set()

        i = 0
        while i < n:
            if s[i] == 'o':
                go.add(i)
                if len(go) == k:
                    break
                i += c + 1
            else:
                i += 1

        if len(go) < k:
            return

        i = n - 1
        while i >= 0:
            if s[i] == 'o':
                back.add(i)
                if len(back) == k:
                    break
                i -= c + 1
            else:
                i -= 1

        if len(back) < k:
            return

        isec = go & back

        ret = []
        for elm in isec:
            go = set()
            i = 0
            while i < n:
                if i == elm:
                    i += 1
                    continue

                if s[i] == 'o':
                    go.add(i)
                    if len(go) == k:
                        break
                    i += c + 1
                else:
                    i += 1

            if len(go) < k:
                ret.append(elm)

    print(*map(lambda x: x + 1, ret), sep='\n')


if __name__ == '__main__':
    main()


Fixed submission:
def main():
    N, K, C = map(int, input().split())
    s = input()

    L = [-1] * K
    R = [-1] * K

    i = 0
    cur = 0
    while i < N and cur < K:
        if s[i] == 'o':
            L[cur] = i
            cur += 1
            i += C + 1
        else:
            i += 1

    i = N - 1
    cur = K - 1
    while i >= 0 and cur >= 0:
        if s[i] == 'o':
            R[cur] = i
            cur -= 1
            i -= C + 1
        else:
            i -= 1

    ans = (left + 1 for left, right in zip(L, R) if left == right)

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
def main():
    n, k, c = map(int, input().split())
    s = input()

    go = set()
    back = set()

    i = 0
    while i < n:
        if s[i] == 'o':
            go.add(i)
            if len(go) == k:
                break
            i += c + 1
        else:
            i += 1

    if len(go) < k:
        return

    i = n - 1
    while i >= 0:
        if s[i] == 'o':
            back.add(i)
            if len(back) == k:
                break
            i -= c + 1
        else:
            i -= 1

    if len(back) < k:
        return

    isec = go & back

    ret = []
    for elm in isec:
        go = set()
        i = 0
        while i < n:
            if i == elm:
                i += 1
                continue

            if s[i] == 'o':
                go.add(i)
                if len(go) == k:
                    break
                i += c + 1
            else:
                i += 1

        if len(go) < k:
            ret.append(elm)

    print(*map(lambda x: x + 1, ret), sep='\n')


if __name__ == '__main__':
    main()


Fixed submission:
def main():
    N, K, C = map(int, input().split())
    s = input()

    L = [-1] * K
    R = [-1] * K

    i = 0
    cur = 0
    while i < N and cur < K:
        if s[i] == 'o':
            L[cur] = i
            cur += 1
            i += C + 1
        else:
            i += 1

    i = N - 1
    cur = K - 1
    while i >= 0 and cur >= 0:
        if s[i] == 'o':
            R[cur] = i
            cur -= 1
            i -= C + 1
        else:
            i -= 1

    ans = (left + 1 for left, right in zip(L, R) if left == right)

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()