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例：查找值为22的记录的过程：low=0high=9mid=4high=3mid=1low=2mid=2282215221822low=3mid=322=22二分查找012345678913151822283456657080mid=(low+high)/2low=mid+1high=mid-1查找成功例：查找值为45的记录的过程：low=0high=9mid=4low=5mid=7low=6mid=5284565453445high=6mid=65645二分查找high=5lowhigh012345678913151822283456657080mid=(low+high)/2low=mid+1high=mid-1查找失败