Everyone is Friends

AtCoder

IDabc272_b

Time2000ms

Memory256MB

Difficulty—

There are $N$ people numbered $1,2,\ldots,N$. $M$ parties were held. $k_i$ people attended the $i$\-th $(1\leq i \leq M)$ party, and they were People $x_{i,1},x_{i,2},\ldots,x_{i,k_i}$. Determine if every two people attended the same party at least once. ## Constraints * $2\leq N \leq 100$ * $1\leq M \leq 100$ * $2\leq k_i \leq N$ * $1\leq x_{i,1}<x_{i,2}<\ldots < x_{i,k_i}\leq N$ * All values in the input are integers. ## Input The input is given from Standard Input in the following format: $N$ $M$ $k_1$ $x_{1,1}$ $x_{1,2}$ $\ldots$ $x_{1,k_1}$ $\vdots$ $k_M$ $x_{M,1}$ $x_{M,2}$ $\ldots$ $x_{M,k_M}$ [samples]

Samples

Input #1

Output #1

Yes

Both Person $1$ and Person $2$ attended the $1$\-st party.
Both Person $2$ and Person $3$ attended the $2$\-nd party.
Both Person $1$ and Person $3$ attended the $3$\-rd party.
Therefore, every two people attended the same party at least once, so the answer is `Yes`.

Input #2

4 2
3 1 2 4
3 2 3 4

Output #2

No

Person $1$ and Person $3$ did not attend the same party, so the answer is `No`.

API Response (JSON)

{
  "problem": {
    "name": "Everyone is Friends",
    "description": {
      "content": "There are $N$ people numbered $1,2,\\ldots,N$. $M$ parties were held. $k_i$ people attended the $i$\\-th $(1\\leq i \\leq M)$ party, and they were People $x_{i,1},x_{i,2},\\ldots,x_{i,k_i}$. Determine if e",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc272_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "There are $N$ people numbered $1,2,\\ldots,N$.\n$M$ parties were held. $k_i$ people attended the $i$\\-th $(1\\leq i \\leq M)$ party, and they were People $x_{i,1},x_{i,2},\\ldots,x_{i,k_i}$.\nDetermine if e...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments