File size: 1,269 Bytes
a9e7957 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | {
"name": "langford_n8__v5_h",
"problem_type": "langford",
"params": {
"n": 8
},
"prompt": "Construct a Langford sequence L(2,8): a sequence of length 16 containing exactly 2 copies of each integer from 1 to 8, such that the two occurrences of each value v are exactly v+1 positions apart (so copies of 1 are 1 position apart, copies of 2 are 2 positions apart, etc.). Example: L(2,3) has solution [2, 3, 1, 2, 1, 3].\n\nReturn seq as a list of 16 integers in 1..8, or state \"UNSATISFIABLE\" if no such sequence exists.\n\nPartial assignment (fixed values that must be respected):\n- seq[4]=7, seq[8]=5, seq[10]=4\nReturn a complete solution consistent with these fixed assignments.",
"satisfiable": true,
"solution": {
"seq": [
2,
3,
8,
2,
7,
3,
6,
1,
5,
1,
4,
8,
7,
6,
5,
4
]
},
"difficulty": {
"solve_time_ms": 1339.8,
"search_space": 20922789888000,
"num_variables": 16,
"num_constraints": 141,
"num_edges": -1,
"backend": "pycsp",
"solve_tier": "hard",
"solve_pct_global": 82.89,
"solve_pct_type": 6.25
},
"partial_assignment": {
"seq": {
"4": 7,
"8": 5,
"10": 4
}
}
}
|