Just K

AtCoder

IDabc249_c

Time2000ms

Memory256MB

Difficulty—

You are given $N$ strings $S_1,S_2,\dots,S_N$ consisting of lowercase English alphabets. Consider choosing some number of strings from $S_1,S_2,\dots,S_N$. Find the maximum number of distinct alphabets that satisfy the following condition: "the alphabet is contained in exactly $K$ of the chosen strings." ## Constraints * $1 \le N \le 15$ * $1 \le K \le N$ * $N$ and $K$ are integers. * $S_i$ is a non-empty string consisting of lowercase English alphabets. * For each integer $i$ such that $1 \le i \le N$, $S_i$ does not contain two or more same alphabets. * If $i \neq j$, then $S_i \neq S_j$. ## Input Input is given from Standard Input in the following format: $N$ $K$ $S_1$ $S_2$ $\vdots$ $S_N$ [samples]

Samples

Input #1

4 2
abi
aef
bc
acg

Output #1

3

When $S_1,S_3$, and $S_4$ are chosen, `a`,`b`, and `c` occur in exactly two of the strings.
There is no way to choose strings so that $4$ or more alphabets occur in exactly $2$ of the strings, so the answer is $3$.

Input #2

2 2
a
b

Output #2

0

You cannot choose the same string more than once.

Input #3

5 2
abpqxyz
az
pq
bc
cy

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Just K",
    "description": {
      "content": "You are given $N$ strings $S_1,S_2,\\dots,S_N$ consisting of lowercase English alphabets. Consider choosing some number of strings from $S_1,S_2,\\dots,S_N$. Find the maximum number of distinct alphabet",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc249_c"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "You are given $N$ strings $S_1,S_2,\\dots,S_N$ consisting of lowercase English alphabets.\nConsider choosing some number of strings from $S_1,S_2,\\dots,S_N$.\nFind the maximum number of distinct alphabet...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments