Who Says a Pun?

AtCoder

IDabc141_e

Time2000ms

Memory256MB

Difficulty—

Given is a string $S$ of length $N$. Find the maximum length of a non-empty string that occurs twice or more in $S$ as contiguous substrings without overlapping. More formally, find the maximum positive integer $len$ such that there exist integers $l_1$ and $l_2$ ( $1 \leq l_1, l_2 \leq N - len + 1$ ) that satisfy the following: * $l_1 + len \leq l_2$ * $S[l_1+i] = S[l_2+i] (i = 0, 1, ..., len - 1)$ If there is no such integer $len$, print $0$. ## Constraints * $2 \leq N \leq 5 \times 10^3$ * $|S| = N$ * $S$ consists of lowercase English letters. ## Input Input is given from Standard Input in the following format: $N$ $S$ [samples]

Samples

Input #1

5
ababa

Output #1

2

The strings satisfying the conditions are: `a`, `b`, `ab`, and `ba`. The maximum length among them is $2$, which is the answer. Note that `aba` occurs twice in $S$ as contiguous substrings, but there is no pair of integers $l_1$ and $l_2$ mentioned in the statement such that $l_1 + len \leq l_2$.

Input #2

2
xy

Output #2

0

No non-empty string satisfies the conditions.

Input #3

13
strangeorange

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Who Says a Pun?",
    "description": {
      "content": "Given is a string $S$ of length $N$. Find the maximum length of a non-empty string that occurs twice or more in $S$ as contiguous substrings without overlapping. More formally, find the maximum positi",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc141_e"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Given is a string $S$ of length $N$.\nFind the maximum length of a non-empty string that occurs twice or more in $S$ as contiguous substrings without overlapping.\nMore formally, find the maximum positi...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments