Doukasen

AtCoder

IDabc223_c

Time2000ms

Memory256MB

Difficulty—

We have $N$ fuses connected in series. The $i$\-th fuse from the left has a length of $A_i$ centimeters and burns at a constant speed of $B_i$ centimeters per second. Consider igniting this object from left and right ends simultaneously. Find the distance between the position where the two flames will meet and the left end of the object. ## Constraints * $1 \leq N \leq 10^5$ * $1 \leq A_i,B_i \leq 1000$ * All values in input are integers. ## Input Input is given from Standard Input in the following format: $N$ $A_1$ $B_1$ $A_2$ $B_2$ $\vdots$ $A_N$ $B_N$ [samples]

Samples

Input #1

Output #1

3.000000000000000

The two flames will meet at $3$ centimeters from the left end of the object.

Input #2

Output #2

3.833333333333333

Input #3

Output #3

8.916666666666668

API Response (JSON)

{
  "problem": {
    "name": "Doukasen",
    "description": {
      "content": "We have $N$ fuses connected in series. The $i$\\-th fuse from the left has a length of $A_i$ centimeters and burns at a constant speed of $B_i$ centimeters per second. Consider igniting this object fro",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc223_c"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "We have $N$ fuses connected in series. The $i$\\-th fuse from the left has a length of $A_i$ centimeters and burns at a constant speed of $B_i$ centimeters per second.\nConsider igniting this object fro...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments