Diverse Word

AtCoder

IDagc022_a

Time2000ms

Memory256MB

Difficulty—

Gotou just received a dictionary. However, he doesn't recognize the language used in the dictionary. He did some analysis on the dictionary and realizes that the dictionary contains all possible **diverse** words in lexicographical order. A word is called **diverse** if and only if it is a nonempty string of English lowercase letters and all letters in the word are distinct. For example, `atcoder`, `zscoder` and `agc` are diverse words while `gotou` and `connect` aren't diverse words. Given a diverse word $S$, determine the next word that appears after $S$ in the dictionary, i.e. the lexicographically smallest diverse word that is lexicographically larger than $S$, or determine that it doesn't exist. Let $X = x_{1}x_{2}...x_{n}$ and $Y = y_{1}y_{2}...y_{m}$ be two distinct strings. $X$ is lexicographically larger than $Y$ if and only if $Y$ is a prefix of $X$ or $x_{j} > y_{j}$ where $j$ is the smallest integer such that $x_{j} \neq y_{j}$. ## Constraints * $1 \leq |S| \leq 26$ * $S$ is a diverse word. ## Input Input is given from Standard Input in the following format: $S$ [samples]

Samples

Input #1

atcoder

Output #1

atcoderb

`atcoderb` is the lexicographically smallest diverse word that is lexicographically larger than `atcoder`. Note that `atcoderb` is lexicographically smaller than `b`.

Input #2

abc

Output #2

abcd

Input #3

zyxwvutsrqponmlkjihgfedcba

Output #3

\-1

This is the lexicographically largest diverse word, so the answer is `-1`.

Input #4

abcdefghijklmnopqrstuvwzyx

Output #4

abcdefghijklmnopqrstuvx

API Response (JSON)

{
  "problem": {
    "name": "Diverse Word",
    "description": {
      "content": "Gotou just received a dictionary. However, he doesn't recognize the language used in the dictionary. He did some analysis on the dictionary and realizes that the dictionary contains all possible **div",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "agc022_a"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Gotou just received a dictionary. However, he doesn't recognize the language used in the dictionary. He did some analysis on the dictionary and realizes that the dictionary contains all possible **div...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments