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HMMT 二月 2002 · 冲刺赛 · 第 17 题

HMMT February 2002 — Guts Round — Problem 17

专题
Discrete Math / 离散数学
难度
L3
来源
HMMT

题目详情

  1. [ ± 8] Find the number of pentominoes (5-square polyominoes) that span a 3-by-3 rect- angle, where polyominoes that are flips or rotations of each other are considered the same polyomino.
解析
  1. Find the number of pentominoes (5-square polyominoes) that span a 3-by-3 rect- angle, where polyominoes that are flips or rotations of each other are considered the same polyomino. Solution: By enumeration, the answer is 6 .