All Subsequences After Deleting One Character

You are given a string `s` of length `n` consisting of lowercase English letters. Consider every string that can be obtained by deleting **exactly one** character from `s` — there are `n` such strings, one for each deletion position. For each resulting string `t`, generate **every non-empty subsequence** of `t`. A subsequence of `t` is obtained by deleting zero or more characters from `t`; the remaining characters must keep the relative order they had in `t` (and therefore the relative order they had in the original string `s`). Collect all strings generated across all `n` deletion results, remove duplicates, and return them sorted in ascending lexicographic order. ### Example Input: `s = "acb"` Deleting one character from `"acb"` produces three strings: - Delete `'a'` → `"cb"`, whose non-empty subsequences are `"c"`, `"b"`, `"cb"` - Delete `'c'` → `"ab"`, whose non-empty subsequences are `"a"`, `"b"`, `"ab"` - Delete `'b'` → `"ac"`, whose non-empty subsequences are `"a"`, `"c"`, `"ac"` Note that the characters of each subsequence keep their original relative order: from `"cb"` the two-character subsequence is `"cb"`, not `"bc"`. Combining all of them, removing duplicates, and sorting lexicographically gives: Output: `["a", "ab", "ac", "b", "c", "cb"]` ### Constraints - `2 <= n <= 15` - `s` consists of lowercase English letters only; `s` may contain repeated characters. - The output must contain each distinct string exactly once, in ascending lexicographic order.