| 1 | |
| 2 | #include <linux/union_find.h>
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| 3 |
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| 4 | |
| 5 | * uf_find - Find the root of a node and perform path compression
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| 6 | * @node: the node to find the root of
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| 7 | *
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| 8 | * This function returns the root of the node by following the parent
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| 9 | * pointers. It also performs path compression, making the tree shallower.
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| 10 | *
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| 11 | * Returns the root node of the set containing node.
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| 12 |
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| 13 | struct uf_node *uf_find(struct uf_node *node)
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| 14 | {
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| 15 | struct uf_node *parent;
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| 16 |
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| 17 | while (node->parent != node) {
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| 18 | parent = node->parent;
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| 19 | node->parent = parent->parent;
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| 20 | node = parent;
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| 21 | }
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| 22 | return node;
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| 23 | }
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| 24 |
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| 25 | |
| 26 | * uf_union - Merge two sets, using union by rank
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| 27 | * @node1: the first node
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| 28 | * @node2: the second node
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| 29 | *
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| 30 | * This function merges the sets containing node1 and node2, by comparing
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| 31 | * the ranks to keep the tree balanced.
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| 32 |
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| 33 | void uf_union(struct uf_node *node1, struct uf_node *node2)
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| 34 | {
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| 35 | struct uf_node *root1 = uf_find(node1);
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| 36 | struct uf_node *root2 = uf_find(node2);
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| 37 |
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| 38 | if (root1 == root2)
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| 39 | return;
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| 40 |
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| 41 | if (root1->rank < root2->rank) {
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| 42 | root1->parent = root2;
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| 43 | } else if (root1->rank > root2->rank) {
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| 44 | root2->parent = root1;
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| 45 | } else {
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| 46 | root2->parent = root1;
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| 47 | root1->rank++;
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| 48 | }
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| 49 | }
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