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1.Alex and broken contest Description One day Alex was creating a contest about his friends, but accidentally deleted it. Fortunately, all the problem 阅读全文
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Walking Between Houses There are nn houses in a row. They are numbered from 11 to nn in order from left to right. Initially you are in the house 11. Y 阅读全文
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一.查询一组的LCA Nearest Common Ancestors A rooted tree is a well-known data structure in computer science and engineering. An example is shown below: In th 阅读全文