Algorithm——LCA(Least Common Ancestors)

Правка en4, от Inversentropir-36, 2020-04-16 13:14:05

1.introduction

As everyone knows, my friend Billy2007 is not good at The algorithm of tree, So I and he write this blog.

LCA , that is, the recent Common ancestor, refers to the root tree, find out one or two nodes u and v recent Common ancestor.

2.how to ask LCA?

For example:

Given a tree with multiple branches, the public ancestor that is closest to the specified two points is requested.

The first line contains three positive integers,

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$ which respectively represent the number of nodes in the tree, the number of inquiries, and the number of root nodes. Next, n-1n-1 rows each contain two positive integers x, yx,y, indicating that there is a directly connected edge between xx node and yy node (the data is guaranteed to form a tree). Next, MM rows each contain two positive integers a, ba, and b, which means that the nearest common ancestor of aa and bb is inquired.

Теги lca, #algorithms

История

 
 
 
 
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en14 Английский Inversentropir-36 2020-04-17 08:42:35 0 (published)
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en5 Английский Inversentropir-36 2020-04-16 13:16:42 4 Tiny change: 'integers, N,M,SN,M,SN,M,S which res' -> 'integers, $N,M,S$ which res'
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en3 Английский Inversentropir-36 2020-04-16 13:10:09 2 Tiny change: 'oduction\nAs ever' -> 'oduction\n\nAs ever'
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en1 Английский Inversentropir-36 2020-04-16 13:06:26 98 Initial revision (saved to drafts)