[ICPC 2021 Nanjing R] Xingqiu's Joke

Luogu
IDLGP9849
Time2000ms
Memory256MB
DifficultyP5
数学递推2021Special JudgeO2优化最大公约数 gcdICPC南京
Once again, Xingqiu hides Chongyun's ice cream into a box with a strange lock. Liyue's summer has been always very hot and Chongyun suffers more because of his excessive yang (positive) energy, so he needs that ice cream desperately. ![](https://cdn.luogu.com.cn/upload/image_hosting/2dtcr426.png) There are two integers $a$ and $b$ on the lock. Chongyun can perform the following three types of operations any number of times: - Minus $1$ from both $a$ and $b$; - Plus $1$ to both $a$ and $b$; - Divide both $a$ and $b$ by one of their common $\textbf{prime}$ factor (that is to say, divide them by a $\textbf{prime}$ $g$ where $a$ and $b$ are both divisible by $g$). The box will be unlocked if either $a$ or $b$ or both become $1$. To help Chongyun gets the ice cream back as quickly as possible, please tell him the minimum number of operations needed to unlock the box. ## Input There are multiple test cases. The first line of the input contains an integer $T$ ($1 \le T \le 300$) indicating the number of test cases. For each test case: The first and only line contains two integers $a$ and $b$ ($1 \le a, b \le 10^9$, $a \ne b$). ## Output For each test case output one line containing one integer indicating the minimum number of operations to make $a$ or $b$ or both equal $1$. [samples] ## Note For the first sample test case, the optimal way is $(4, 7) \rightarrow (3, 6) \rightarrow (1, 2)$. For the second sample test case, the optimal way is to apply the first type of operation $7$ times. For the third sample test case, the optimal way is $(32, 84) \rightarrow (16, 42) \rightarrow (15, 41) \rightarrow (14, 40) \rightarrow (13, 39) \rightarrow (1, 3)$. For the fourth sample test case, the optimal way is $(11, 35) \rightarrow (12, 36) \rightarrow (6, 18) \rightarrow (2, 6) \rightarrow (1, 3)$.
Samples
Input #1
5
4 7
9 8
32 84
11 35
2 1
Output #1
2
7
5
4
0
API Response (JSON)
{
  "problem": {
    "name": "[ICPC 2021 Nanjing R] Xingqiu's Joke",
    "description": {
      "content": "Once again, Xingqiu hides Chongyun's ice cream into a box with a strange lock. Liyue's summer has been always very hot and Chongyun suffers more because of his excessive yang (positive) energy, so he ",
      "description_type": "Markdown"
    },
    "platform": "Luogu",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": {
      "LuoguStyle": "P5"
    },
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "LGP9849"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Once again, Xingqiu hides Chongyun's ice cream into a box with a strange lock. Liyue's summer has been always very hot and Chongyun suffers more because of his excessive yang (positive) energy, so he ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}
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