打卡记录

参加考试的最大学生数（压缩状态DP）

链接

class Solution:def maxStudents(self, seats: List[List[str]]) -> int:m, n = len(seats), len(seats[0])# a[i] 是第 i 排可用椅子的下标集合a = [sum((c == '.') << j for j, c in enumerate(s)) for s in seats]f = [[0] * (1 << n) for _ in range(m)]for j in range(1, 1 << n):lb = j & -jf[0][j] = f[0][j & ~(lb * 3)] + 1for i in range(1, m):j = a[i]while j:  # 枚举 a[i] 的子集 jf[i][j] = f[i - 1][a[i - 1]]  # 第 i 排空着s = jwhile s:  # 枚举 j 的子集 sif (s & (s >> 1)) == 0:  # s 没有连续的 1t = a[i - 1] & ~(s << 1 | s >> 1)  # 去掉不能坐人的位置f[i][j] = max(f[i][j], f[i - 1][t] + f[0][s])s = (s - 1) & jj = (j - 1) & a[i]f[i][0] = f[i - 1][a[i - 1]]return f[-1][a[-1]]