Wide Flip

AtCoder

IDarc088_b

Time2000ms

Memory256MB

Difficulty—

You are given a string $S$ consisting of `0` and `1`. Find the maximum integer $K$ not greater than $|S|$ such that we can turn all the characters of $S$ into `0` by repeating the following operation some number of times. * Choose a contiguous segment $[l,r]$ in $S$ whose length is at least $K$ (that is, $r-l+1\geq K$ must be satisfied). For each integer $i$ such that $l\leq i\leq r$, do the following: if $S_i$ is `0`, replace it with `1`; if $S_i$ is `1`, replace it with `0`. ## Constraints * $1\leq |S|\leq 10^5$ * $S_i(1\leq i\leq N)$ is either `0` or `1`. ## Input Input is given from Standard Input in the following format: $S$ [samples]

Samples

Input #1

Output #1

2

We can turn all the characters of $S$ into `0` by the following operations:

*   Perform the operation on the segment $S[1,3]$ with length $3$. $S$ is now `101`.
*   Perform the operation on the segment $S[1,2]$ with length $2$. $S$ is now `011`.
*   Perform the operation on the segment $S[2,3]$ with length $2$. $S$ is now `000`.

Input #2

100000000

Output #2

Input #3

00001111

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Wide Flip",
    "description": {
      "content": "You are given a string $S$ consisting of `0` and `1`. Find the maximum integer $K$ not greater than $|S|$ such that we can turn all the characters of $S$ into `0` by repeating the following operation ",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "arc088_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "You are given a string $S$ consisting of `0` and `1`. Find the maximum integer $K$ not greater than $|S|$ such that we can turn all the characters of $S$ into `0` by repeating the following operation ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments