07 2017 档案
摘要:Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. Note that after a tie, the next ranking num
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摘要:Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation. Note: Example 1: Exa
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摘要:与树的前中后序遍历的DFS思想不同,层次遍历用到的是BFS思想。一般DFS用递归去实现(也可以用栈实现),BFS需要用队列去实现。 层次遍历的步骤是: 1.对于不为空的结点,先把该结点加入到队列中 2.从队中拿出结点,如果该结点的左右结点不为空,就分别把左右结点加入到队列中 3.重复以上操作直到队列
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