排列组合 - Problem Set - XSM

	ID	Problem Show tags Hide tags	AC / Tried	Difficulty
	578	P578 希蒙摸球-1 排列组合 DFS	4 / 12	9
	579	P579 希蒙摸球-2 DFS 排列组合	4 / 7	10
	580	P580 希蒙摸球-3 DFS 排列组合	4 / 8	10
	581	P581 希蒙摸球-4 DFS 排列组合	4 / 13	9

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