Bittipeli

import java.util.*;

public class BittipeliTehtava {

    private static int numberOfSequences(String bits) {
        int length = bits.length();
        int sequences = 1;
        for (int i = 1; i < length; i++) {
            if (bits.charAt(i) != bits.charAt(i - 1)) {
                sequences++;
            }
        }
        return sequences;
    }

    private static int midSequenceIndex(String bits, int sequences) {
        int half = sequences / 2;
        int index = 1;
        int count = 1;
        while (true) {
            if (bits.charAt(index) != bits.charAt(index - 1)) {
                count++;
            }
            if (count > half) {
                break;
            }
            index++;
        }
        return index;
    }

    private static List<Integer> removeBits(String bits, int midSequenceIndex) {
        List<Integer> moves = new LinkedList<>();
        Stack<Character> stackOfBits = new Stack<>();
        int currentLongSequence = 0;
        
        for (int i = 0; i < midSequenceIndex; i++) {
            stackOfBits.push(bits.charAt(i));
            if (i >= 1 && bits.charAt(i) != bits.charAt(i - 1)
                    && bits.charAt(i) == bits.charAt(i + 1)) {
                currentLongSequence++;
            } else if (i == 0 && bits.charAt(i) == bits.charAt(i + 1)) {
                currentLongSequence++;
            }
        }

        int index = midSequenceIndex;
        boolean stackChanged = true;

        while (stackChanged) {
            stackChanged = false;
            if (stackOfBits.isEmpty()) {
                break;
            }
            
            if (index < bits.length()) {
                char currentChar = bits.charAt(index);
                while (index < bits.length() && bits.charAt(index) == currentChar) {
                    char toAdd = bits.charAt(index);
                    char lastAdded = stackOfBits.peek();
                    if (toAdd != lastAdded && (index < bits.length() - 1 && toAdd == bits.charAt(index + 1))) {
                        currentLongSequence++;
                    }
                    stackOfBits.push(toAdd);
                    index++;
                    stackChanged = true;
                }
            }
            
            if (stackOfBits.size() >= 2) {
                char lastAdded = stackOfBits.pop();
                char beforeThat = stackOfBits.peek();
                if (lastAdded == beforeThat) {
                    while (!stackOfBits.isEmpty() && lastAdded == stackOfBits.peek()) {
                        stackOfBits.pop();
                    }
                    moves.add(currentLongSequence);                   
                    currentLongSequence--;
                    stackChanged = true;
                    
                    if (!stackOfBits.isEmpty()) {
                        char topOfStack = stackOfBits.pop();
                        if ((stackOfBits.isEmpty() || (topOfStack != stackOfBits.peek()))
                                && index < bits.length()) {
                            currentLongSequence++;
                        }
                        stackOfBits.push(topOfStack);
                    }
                } else {
                    stackOfBits.push(lastAdded);
                }              
            }
        }      
        if (stackOfBits.isEmpty()) {
            return moves;
        }        
        return null;
    }

    public static void main(String[] args) {
        IO io = new IO();
        String bits = io.next();

        int numberOfSequences = numberOfSequences(bits);
        int midSequenceIndex = midSequenceIndex(bits, numberOfSequences);
        
        List<Integer> moves = removeBits(bits, midSequenceIndex);
        if (moves == null) {
            io.println("QAQ");
        } else {
            io.println(moves.size());
            StringBuilder output = new StringBuilder();
            output.append(moves.get(0));
            for (int i = 1; i < moves.size(); i++) {
                output.append(" ");
                output.append(moves.get(i));
            }
            io.println(output.toString());
        }
        
        io.close();
    }
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: WRONG ANSWER

Test 4

Group: 1

Verdict: WRONG ANSWER

Test 5

Group: 1

Verdict: WRONG ANSWER

Test 6

Group: 1

Verdict: ACCEPTED

Test 7

Group: 1

Verdict: ACCEPTED

Test 8

Group: 1

Verdict: ACCEPTED

Test 9

Group: 1

Verdict: ACCEPTED

Test 10

Group: 1

Verdict: WRONG ANSWER

Test 11

Group: 1

Verdict: ACCEPTED

Test 12

Group: 1

Verdict: WRONG ANSWER

Test 13

Group: 1

Verdict: ACCEPTED

Test 14

Group: 1

Verdict: ACCEPTED

Test 15

Group: 1

Verdict: ACCEPTED

Test 16

Group: 1

Verdict: ACCEPTED

Test 17

Group: 1

Verdict: ACCEPTED

Test 18

Group: 1

Verdict: ACCEPTED

Test 19

Group: 1

Verdict: ACCEPTED

Test 20

Group: 1

Verdict: ACCEPTED

Test 21

Group: 2

Verdict: ACCEPTED

Test 22

Group: 2

Verdict: WRONG ANSWER

Test 23

Group: 2

Verdict: WRONG ANSWER

Test 24

Group: 2

Verdict: ACCEPTED

Test 25

Group: 2

Verdict: ACCEPTED

Test 26

Group: 2

Verdict: WRONG ANSWER

Test 27

Group: 2

Verdict: WRONG ANSWER

Test 28

Group: 2

Verdict: WRONG ANSWER

Test 29

Group: 2

Verdict: ACCEPTED

Test 30

Group: 2

Verdict: ACCEPTED

Test 31

Group: 2

Verdict: ACCEPTED

Test 32

Group: 2

Verdict: ACCEPTED

Test 33

Group: 2

Verdict: ACCEPTED

Test 34

Group: 2

Verdict: WRONG ANSWER

Test 35

Group: 2

Verdict: ACCEPTED

Test 36

Group: 2

Verdict: ACCEPTED

Test 37

Group: 2

Verdict: ACCEPTED

Test 38

Group: 2

Verdict: WRONG ANSWER

Test 39

Group: 2

Verdict: ACCEPTED

Test 40

Group: 2

Verdict: WRONG ANSWER

Test 41

Group: 3

Verdict: ACCEPTED

Test 42

Group: 3

Verdict: WRONG ANSWER

Test 43

Group: 3

Verdict: ACCEPTED

Test 44

Group: 3

Verdict: ACCEPTED

Test 45

Group: 3

Verdict: ACCEPTED

Test 46

Group: 3

Verdict: ACCEPTED

Test 47

Group: 3

Verdict: ACCEPTED

Test 48

Group: 3

Verdict: ACCEPTED

Test 49

Group: 3

Verdict: WRONG ANSWER

Test 50

Group: 3

Verdict: WRONG ANSWER

Test 51

Group: 3

Verdict: ACCEPTED

Test 52

Group: 3

Verdict: ACCEPTED

Test 53

Group: 3

Verdict: ACCEPTED

Test 54

Group: 3

Verdict: ACCEPTED

Test 55

Group: 3

Verdict: ACCEPTED

Test 56

Group: 3

Verdict: ACCEPTED

Test 57

Group: 3

Verdict: ACCEPTED

Test 58

Group: 3

Verdict: WRONG ANSWER

Test 59

Group: 3

Verdict: ACCEPTED

Test 60

Group: 3

Verdict: WRONG ANSWER

Test 61

Group: 4

Verdict: ACCEPTED

Test 62

Group: 4

Verdict: WRONG ANSWER

Test 63

Group: 4

Verdict: ACCEPTED

Test 64

Group: 4

Verdict: ACCEPTED

Test 65

Group: 4

Verdict: ACCEPTED

Test 66

Group: 4

Verdict: WRONG ANSWER

Test 67

Group: 4

Verdict: ACCEPTED

Test 68

Group: 4

Verdict: ACCEPTED

Test 69

Group: 4

Verdict: ACCEPTED

Test 70

Group: 4

Verdict: ACCEPTED

Test 71

Group: 4

Verdict: WRONG ANSWER

Test 72

Group: 4

Verdict: ACCEPTED

Test 73

Group: 4

Verdict: ACCEPTED

Test 74

Group: 4

Verdict: ACCEPTED

Test 75

Group: 4

Verdict: ACCEPTED

Test 76

Group: 4

Verdict: ACCEPTED

Test 77

Group: 4

Verdict: ACCEPTED

Test 78

Group: 4

Verdict: WRONG ANSWER

Test 79

Group: 4

Verdict: TIME LIMIT EXCEEDED

Test 80

Group: 4

Verdict: ACCEPTED