{
  "name": "knight_tour_n7__v2_nh",
  "problem_type": "knight_tour",
  "params": {
    "n": 7
  },
  "prompt": "Find an open knight's tour on an 7x7 chessboard that starts at cell 0 (row 0, column 0). A knight's tour visits every cell exactly once via knight moves; cells are numbered in row-major order so cell k is at row k//7, column k%7. A knight move between cells a and b changes the row by 1 and column by 2, or row by 2 and column by 1.\n\nReturn a list of 49 integers giving the cell visited at each step (a permutation of 0..48 starting with 0), or state \"UNSATISFIABLE\" if no such tour exists.",
  "satisfiable": true,
  "solution": {
    "x": [
      0,
      15,
      30,
      17,
      2,
      7,
      16,
      3,
      18,
      5,
      20,
      11,
      6,
      19,
      24,
      9,
      4,
      13,
      26,
      39,
      48,
      33,
      46,
      41,
      32,
      27,
      12,
      25,
      10,
      1,
      14,
      23,
      8,
      21,
      36,
      45,
      40,
      31,
      22,
      35,
      44,
      29,
      42,
      37,
      28,
      43,
      38,
      47,
      34
    ]
  },
  "difficulty": {
    "solve_time_ms": 2845.5,
    "search_space": 608281864034267560872252163321295376887552831379210240000000000,
    "num_variables": 49,
    "num_constraints": 52,
    "num_edges": -1,
    "backend": "pycsp",
    "solve_tier": "hard",
    "solve_pct_global": 95.68,
    "solve_pct_type": 37.5
  },
  "partial_assignment": null
}