【30】烧一根不均匀的绳要用一个小时,如何用它来断定半个小时?
烧一根不均匀的绳,重新烧到尾总共须要1个小时。现在有若干条材质相同的绳子,问如何用烧绳的办法来计时一个小时十五分钟呢? (微软的笔试题)
1. burn from both end?
2. i have a feeling this may be wrong, but: burn two ropes, one from one end and the other from both... so after 30', stop the one-end rope from burning... now:
burn another 1hour one plus this remaining rope from both end.......
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