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This patch implements a union-find data structure in the kernel library, which includes operations for allocating nodes, freeing nodes, finding the root of a node, and merging two nodes. Signed-off-by: Xavier <xavier_qy@163.com> Signed-off-by: Tejun Heo <tj@kernel.org>
49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/union_find.h>
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/**
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* uf_find - Find the root of a node and perform path compression
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* @node: the node to find the root of
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*
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* This function returns the root of the node by following the parent
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* pointers. It also performs path compression, making the tree shallower.
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*
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* Returns the root node of the set containing node.
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*/
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struct uf_node *uf_find(struct uf_node *node)
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{
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struct uf_node *parent;
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while (node->parent != node) {
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parent = node->parent;
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node->parent = parent->parent;
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node = parent;
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}
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return node;
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}
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/**
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* uf_union - Merge two sets, using union by rank
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* @node1: the first node
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* @node2: the second node
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*
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* This function merges the sets containing node1 and node2, by comparing
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* the ranks to keep the tree balanced.
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*/
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void uf_union(struct uf_node *node1, struct uf_node *node2)
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{
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struct uf_node *root1 = uf_find(node1);
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struct uf_node *root2 = uf_find(node2);
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if (root1 == root2)
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return;
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if (root1->rank < root2->rank) {
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root1->parent = root2;
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} else if (root1->rank > root2->rank) {
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root2->parent = root1;
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} else {
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root2->parent = root1;
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root1->rank++;
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}
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}
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