Neighbors

AtCoder

IDabc231_d

Time2000ms

Memory256MB

Difficulty—

Determine whether there is a way to line up $N$ people, numbered $1$ to $N$, in a row side by side to satisfy all of the $M$ conditions in the following format. * Condition: Person $A_i$ and Person $B_i$ are adjacent. ## Constraints * $2 \leq N \leq 10^5$ * $0 \leq M \leq 10^5$ * $1\leq A_i < B_i \leq N$ * All pairs $(A_i,B_i)$ are distinct. ## Input Input is given from Standard Input in the following format: $N$ $M$ $A_1$ $B_1$ $\vdots$ $A_M$ $B_M$ [samples]

Samples

Input #1

4 2
1 3
2 3

Output #1

Yes

One way to satisfy all the conditions is to line them up in the order $4,1,3,2$.

Input #2

Output #2

No

There is no way to line them up to satisfy all the conditions.

API Response (JSON)

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  "problem": {
    "name": "Neighbors",
    "description": {
      "content": "Determine whether there is a way to line up $N$ people, numbered $1$ to $N$, in a row side by side to satisfy all of the $M$ conditions in the following format. *   Condition: Person $A_i$ and Person",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc231_d"
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  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Determine whether there is a way to line up $N$ people, numbered $1$ to $N$, in a row side by side to satisfy all of the $M$ conditions in the following format.\n\n*   Condition: Person $A_i$ and Person...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

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