SAP智力题-----Locks and chains

There are 2 rings on door and wall, if you put a chain through the rings and use a lock to lock the two ends of the chain, then the door is locked. One key can unlock only one lock. Now you have enough chains.
(1) how to lock the door with 3 locks, and all 3 keys are necessary to unlock the door;
(2) how to lock the door with 3 locks, and any 1 key is necessary and sufficient to unlock the door;
(3) how to lock the door with 3 locks, and any 2 keys are necessary and sufficient to unlock the door;
(4) how to lock the door with 5 locks, and any 3 keys are necessary and sufficient to unlock the door;
https://www.sdn.sap.com/irj/scn/forum?forumID=410

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• 回复：SAP智力题-----Locks and chains -Windows8- ♂ (99 bytes) () 06/11/2009 postreply 10:24:11