Given a string consisting of only the characters + and -, generate all possible strings after flipping any pair of consecutive + characters to --. Return the list of all possible resulting strings. Each flip must change exactly two consecutive + to --.
Example 1
Input: ++--+++
Output: [----+++,++----+,++--+--]
Explanation: Flipping each pair of consecutive + in positions 0-1, 4-5, and 5-6 yields the three possible strings.
Example 2
Input: ++++
Output: [--++,+--+,++--]
Explanation: Flipping pairs at positions 0-1, 1-2, and 2-3.
Constraints
Case 1
Input: '+-+-+++'
Expected: ['+-+-+--','+-+---+']
Case 2
Input: '--++--'
Expected: ['------']
Case 3
Input: '+++'
Expected: ['--+','+--']
Case 4
Input: '--+--'
Expected: []