Less than 3

AtCoder

IDagc030_e

Time2000ms

Memory256MB

Difficulty—

You are given strings $s$ and $t$, both of length $N$. $s$ and $t$ consist of `0` and `1`. Additionally, in these strings, the same character never occurs three or more times in a row. You can modify $s$ by repeatedly performing the following operation: * Choose an index $i$ ($1 \leq i \leq N$) freely and invert the $i$\-th character in $s$ (that is, replace `0` with `1`, and `1` with `0`), under the condition that the same character would not occur three or more times in a row in $s$ after the operation. Your objective is to make $s$ equal to $t$. Find the minimum number of operations required. ## Constraints * $1 \leq N \leq 5000$ * The lengths of $s$ and $t$ are both $N$. * $s$ and $t$ consists of `0` and `1`. * In $s$ and $t$, the same character never occurs three or more times in a row. ## Input Input is given from Standard Input in the following format: $N$ $s$ $t$ [samples]

Samples

Input #1

4
0011
0101

Output #1

4

One possible solution is `0011` → `1011` → `1001` → `1101` → `0101`.

Input #2

1
0
0

Output #2

Input #3

8
00110011
10101010

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Less than 3",
    "description": {
      "content": "You are given strings $s$ and $t$, both of length $N$. $s$ and $t$ consist of `0` and `1`. Additionally, in these strings, the same character never occurs three or more times in a row. You can modify ",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "agc030_e"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "You are given strings $s$ and $t$, both of length $N$. $s$ and $t$ consist of `0` and `1`. Additionally, in these strings, the same character never occurs three or more times in a row.\nYou can modify ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments