PUZZLE #2911: Watershed D8 Flow Model (diff 4)

watershed learn difficulty: 4/7 simulate author: system unsolved audits passed

A 8×8 elevation grid. Compute D8 flow accumulation — drainage area per cell maps to letters.

DATA

Elevation	`[15, 43, 73, 29, 32, 74, 65, 14], [49, 40, 36, 25, 46, 59, 36, 87], [62, 49, 22, 58, 21, 44, 16, 14], [36, 26, 88, 82, 19, 80, 43, 44], [63, 15, 69, 66, 20, 49, 25, 62], [70, 37, 73, 45, 14, 14, 13, 77], [68, 43, 50, 84, 10, 42, 73, 59], [76, 70, 73, 63, 83, 68, 26, 62]`
Grid Size	`8`
N Chars	`6`
Hint	`For each cell: find lowest neighbor (8-directional). Water flows that way. Accumulate flow from upstream cells. Sort outlet cells by accumulation -> letters.`
Answer Format	`lowercase letters, no spaces or punctuation`

{
  "type": "watershed",
  "elevation": [
    [
      15,
      43,
      73,
      29,
      32,
      74,
      65,
      14
    ],
    [
      49,
      40,
      36,
      25,
      46,
      59,
      36,
      87
    ],
    [
      62,
      49,
      22,
      58,
      21,
      44,
      16,
      14
    ],
    [
      36,
      26,
      88,
      82,
      19,
      80,
      43,
      44
    ],
    [
      63,
      15,
      69,
      66,
      20,
      49,
      25,
      62
    ],
    [
      70,
      37,
      73,
      45,
      14,
      14,
      13,
      77
    ],
    [
      68,
      43,
      50,
      84,
      10,
      42,
      73,
      59
    ],
    [
      76,
      70,
      73,
      63,
      83,
      68,
      26,
      62
    ]
  ],
  "grid_size": 8,
  "n_chars": 6,
  "hint": "For each cell: find lowest neighbor (8-directional). Water flows that way. Accumulate flow from upstream cells. Sort outlet cells by accumulation -> letters.",
  "answer_format": "lowercase letters, no spaces or punctuation"
}

author's note: Audited: watershed diff 4