Remove One Character

AtCoder

IDarc130_a

Time2000ms

Memory256MB

Difficulty—

You are given a string $S$ of length $N$. For each $1\leq i\leq N$, let $S_i$ denote the string obtained by deleting the $i$\-th character from $S$. Find the number of pairs of integers $(i,j)$ that satisfy both of the conditions below. * $1\leq i < j\leq N$ * $S_i = S_j$ ## Constraints * $2\leq N\leq 3\times 10^5$ * $S$ is a string of length $N$ consisting of lowercase English letters. ## Input Input is given from Standard Input in the following format: $N$ $S$ [samples]

Samples

Input #1

7
abbbcca

Output #1

4

Here are the strings $S_i$ in order: `bbbcca`, `abbcca`, `abbcca`, `abbcca`, `abbbca`, `abbbca`, `abbbcc`.
The following $4$ pairs $(i,j)$ satisfy the conditions.

*   $(i,j) = (2,3)$
*   $(i,j) = (2,4)$
*   $(i,j) = (3,4)$
*   $(i,j) = (5,6)$

Input #2

4
xxxx

Output #2

Input #3

2
pp

Output #3

Input #4

2
st

Output #4

API Response (JSON)

{
  "problem": {
    "name": "Remove One Character",
    "description": {
      "content": "You are given a string $S$ of length $N$. For each $1\\leq i\\leq N$, let $S_i$ denote the string obtained by deleting the $i$\\-th character from $S$. Find the number of pairs of integers $(i,j)$ that s",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "arc130_a"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "You are given a string $S$ of length $N$. For each $1\\leq i\\leq N$, let $S_i$ denote the string obtained by deleting the $i$\\-th character from $S$.\nFind the number of pairs of integers $(i,j)$ that s...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments