[SNCPC2019] Digit Product

Luogu
IDLGP9651
Time1000ms
Memory256MB
DifficultyP1
2019O2优化陕西省赛/邀请赛
Define the ''digit product'' $f(x)$ of a positive integer $x$ as the product of all its digits. For example, $f(1234) = 1 \times 2 \times 3 \times 4 = 24$, and $f(100) = 1 \times 0 \times 0 = 0$. Given two integers $l$ and $r$, please calculate the following value: $$(\prod_{i=l}^r f(i)) \mod (10^9+7)$$ In case that you don't know what $\prod$ represents, the above expression is the same as $$(f(l) \times f(l+1) \times \dots \times f(r)) \mod (10^9+7)$$ ## Input There are multiple test cases. The first line of the input contains an integer $T$ (about $10^5$), indicating the number of test cases. For each test case: The first and only line contains two integers $l$ and $r$ ($1 \le l \le r \le 10^9$), indicating the given two integers. The integers are given without leading zeros. ## Output For each test case output one line containing one integer indicating the answer. [samples] ## Note For the first sample test case, the answer is $9! \mod (10^9+7) = 362880$. For the second sample test case, the answer is $(f(97) \times f(98) \times f(99)) \mod (10^9+7) = (9 \times 7 \times 9 \times 8 \times 9 \times 9) \mod (10^9+7) = 367416$.
Samples
Input #1
2
1 9
97 99
Output #1
362880
367416
API Response (JSON)
{
  "problem": {
    "name": "[SNCPC2019] Digit Product",
    "description": {
      "content": "Define the ''digit product'' $f(x)$ of a positive integer $x$ as the product of all its digits. For example, $f(1234) = 1 \\times 2 \\times 3 \\times 4 = 24$, and $f(100) = 1 \\times 0 \\times 0 = 0$. Giv",
      "description_type": "Markdown"
    },
    "platform": "Luogu",
    "limit": {
      "time_limit": 1000,
      "memory_limit": 262144
    },
    "difficulty": {
      "LuoguStyle": "P1"
    },
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "LGP9651"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Define the ''digit product'' $f(x)$ of a positive integer $x$ as the product of all its digits. For example, $f(1234) = 1 \\times 2 \\times 3 \\times 4 = 24$, and $f(100) = 1 \\times 0 \\times 0 = 0$.\n\nGiv...",
      "is_translate": false,
      "language": "English"
    }
  ]
}
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