Postdocs

AtCoder

IDnomura2020_b

Time2000ms

Memory256MB

Difficulty—

For a string $S$ consisting of the uppercase English letters `P` and `D`, let the _doctoral and postdoctoral quotient_ of $S$ be the total number of occurrences of `D` and `PD` in $S$ as contiguous substrings. For example, if $S =$ `PPDDP`, it contains two occurrences of `D` and one occurrence of `PD` as contiguous substrings, so the doctoral and postdoctoral quotient of $S$ is $3$. We have a string $T$ consisting of `P`, `D`, and `?`. Among the strings that can be obtained by replacing each `?` in $T$ with `P` or `D`, find one with the maximum possible doctoral and postdoctoral quotient. ## Constraints * $1 \leq |T| \leq 2 \times 10^5$ * $T$ consists of `P`, `D`, and `?`. ## Input Input is given from Standard Input in the following format: $T$ [samples]

Samples

Input #1

PD?D??P

Output #1

PDPDPDP

This string contains three occurrences of `D` and three occurrences of `PD` as contiguous substrings, so its doctoral and postdoctoral quotient is $6$, which is the maximum doctoral and postdoctoral quotient of a string obtained by replacing each `?` in $T$ with `P` or `D`.

Input #2

P?P?

Output #2

PDPD

API Response (JSON)

{
  "problem": {
    "name": "Postdocs",
    "description": {
      "content": "For a string $S$ consisting of the uppercase English letters `P` and `D`, let the _doctoral and postdoctoral quotient_ of $S$ be the total number of occurrences of `D` and `PD` in $S$ as contiguous su",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "nomura2020_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "For a string $S$ consisting of the uppercase English letters `P` and `D`, let the _doctoral and postdoctoral quotient_ of $S$ be the total number of occurrences of `D` and `PD` in $S$ as contiguous su...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments